One of the possible reasons that the administrator is not seeing the printers within his Horizon Desktop session is that printing is disabled in the Horizon Desktop Pool. Printing is a feature that allows users to print from a remote desktop to any local or network printer available on their client device. Printing can be enabled or disabled for each desktop pool by using the VMware Integrated Printing feature.
VMware Integrated Printing is a feature that supports client printer redirection, location-based printing, and persistent print settings. Client printer redirection enables users to print from a remote desktop to any local or network printer available on their client device. Location-based printing enables users to print to network printers that are physically near their client device. Persistent print settings enable users to retain their print settings across sessions.
To enable or disable printing for a desktop pool, the administrator needs to follow these steps:
In Horizon Console, select Inventory > Desktops.
Select the desktop pool and click Edit.
In the Edit Desktop Pool dialog box, select the VMware Integrated Printing tab.
Select or clear the Enable VMware Integrated Printing check box.
Click OK.
If printing is disabled for a desktop pool, users will not see any printers within their Horizon Desktop session, even if they have installed the VMware Integrated Printing feature in the Horizon Agent and the Horizon Client. Therefore, to resolve this issue, the administrator needs to enable printing for the desktop pool by selecting the Enable VMware Integrated Printing check box.
The other options are not likely to be the reason that the administrator is not seeing the printers within his Horizon Desktop session:
Port TCP 9427 is disabled: This port is used by the VMware Integrated Printing feature for communication between the Horizon Agent and the Horizon Client. If this port is disabled, users might experience printing errors or delays, but they should still see the printers within their Horizon Desktop session.
The VMware Integrated Printing feature is not installed in the Horizon Client: This feature is installed by default in the Horizon Client for Windows, Mac, Linux, Chrome, and HTML Access. If this feature is not installed in the Horizon Client, users might not be able to print from their remote desktops, but they should still see the printers within their Horizon Desktop session.
Port TCP 32111 is disabled: This port is used by ThinPrint for communication between the Horizon Agent and the ThinPrint Client. ThinPrint is a legacy printing feature that has been replaced by VMware Integrated Printing. If this port is disabled, users might experience printing errors or delays with ThinPrint, but they should still see the printers within their Horizon Desktop session if they use VMware Integrated Printing.
References: Configuring VMware Integrated Printing, Enable or Disable Printing for a Desktop Pool, and
[VMware Horizon 8.x Professional Course]

VMware App Volumes is a real-time application delivery system that allows administrators to assign applications to users and groups in Horizon. App Volumes uses virtual disks called packages to store and deliver applications. When a user logs on to a desktop, the App Volumes agent attaches the assigned packages to the desktop and merges them with the OS disk. The user can then access the applications as if they were natively installed.
App Volumes is a suitable solution for deploying an application to specific users in an instant-clone desktop environment with the following characteristics:
The application needs to be updated very frequently: App Volumes allows administrators to update applications in real time by using the update or push-image operations. These operations replace the existing packages with new ones that have the latest updates applied, without affecting the user data or settings. The updated packages are delivered to the users at the next login or refresh.
The application needs to be installed as soon as possible: App Volumes allows administrators to install applications quickly and easily by using a clean packaging system and capturing the application installation process. The resulting package can be assigned to users or groups immediately, without requiring any recomposing or rebooting of the desktops.
The application is not multi-user aware: App Volumes allows administrators to deliver applications that are not multi-user aware by using writable volumes. Writable volumes are user-specific virtual disks that store user-installed applications, data, and settings. Writable volumes can be attached to desktops along with application packages, and they can isolate the user-installed applications from the system-installed applications.
The other options are not suitable for meeting the requirements:
VMware Horizon Published Application: This option allows administrators to publish applications from RDS hosts to users in Horizon. However, this option requires a separate RDS infrastructure and licensing, and it does not support instant updates or writable volumes for user-installed applications.
VMware Dynamic Environment Manager: This option allows administrators to manage user profiles and policies in Horizon. However, this option does not deliver or update applications, and it does not support writable volumes for user-installed applications.
VMware ThinApp: This option allows administrators to package applications into portable executables that can run on any Windows system without installation. However, this option requires a separate packaging process and licensing, and it does not support instant updates or writable volumes for user-installed applications.
References: App Volumes Architecture, Updating Applications in Real Time, Writable Volumes Overview, and [VMware Horizon 8.x Professional Course]

VMware Horizon Agent for Linux is a software component that enables Linux machines to be used as remote desktops or published applications in a Horizon environment. Horizon Agent for Linux supports several features that enhance the user experience and manageability of Linux desktops and applications, such as USB redirection, display protocol PCoIP, multiple-session mode, single sign-on, smart card authentication, and 3D graphics34. However, Horizon Agent for Linux does not support location based printing or session collaboration features that are available for Windows machines5. Also, Horizon Agent for Linux does not require installation registration as it automatically registers with the Connection Server when the viewagent service is started6. References := 3: VMware Horizon 8 Documentation: Horizon Agent for Linux 4: VMware Horizon 8 Documentation: Features Supported by Horizon Agent for Linux 5: VMware Horizon 8 Documentation: Features Not Supported by Horizon Agent for Linux 6: VMware Horizon 8 Documentation: Install Horizon Agent on a Linux Machine

For instant-clone operations in Active Directory, the user account used by VMware Horizon needs specific permissions to manage computer objects effectively. These include the ability to create and delete child objects and computer objects, as well as read and write all properties of those objects. These permissions ensure that Horizon can create, modify, and clean up computer accounts associated with instant clones, facilitating seamless desktop provisioning and management.

Explanation
To entitle users and groups to pools, you need to perform the following steps:
During pool creation in the entitlement pane, click on add, search for users and groups in the Active Directory, continue and finish the pool creation. This option allows you to entitle users and groups to a desktop or application pool at the same time as you create the pool3.
Navigate to Inventory > Desktops > check mark a pool > click on Add Entitlement. This option allows you to add entitlements to an existing desktop or application pool after you create the pool4.
Navigate to Users and Groups > Entitlements > click on Entitlements > click on Add Entitlements, search for users and groups in the Users pane and add the desired desktop pool in the next pane Desktop Pools. This option allows you to review and manage the entitlements for users and groups from a single location5.
The other options are not required or valid for entitling users and groups to pools. Running the Active Directory entitlement script in the golden master is not necessary as Horizon 8 automatically synchronizes with Active Directory domains that are configured in Horizon Console6. Specifying the desired Active Directory OU for the VMs during pool creation does not automatically add the preconfigured associated user group to the Horizon entitlements as you still need to select the users or groups from the search results7. References := 3: VMware Horizon 8 Documentation: Add Entitlements During Pool Creation 4:
VMware Horizon 8 Documentation: Add Entitlements After Pool Creation 5: VMware Horizon 8 Documentation: Review and Manage Entitlements 6: VMware Horizon 8 Documentation: Active Directory Requirements forHorizon Connection Server 7: VMware Horizon 8 Documentation: Create an Automated Desktop Pool