A single-threaded application is an application that can only execute one task or process at a time. A single-threaded application can only utilize one CPU core, regardless of how many cores are available or assigned to the virtual machine. Therefore, adding more vCPU cores to the VM will not improve the performance of the application, as it will still be limited by the speed and capacity of one core12.
To troubleshoot this issue, the administrator should check if the application is single-threaded or multi-threaded. This can be done by using tools such as Task Manager, Performance Monitor, or Process Explorer on Windows, or top, htop, or ps on Linux34. If the application is single-threaded, the administrator should consider the following options:
Reduce the number of vCPU cores on the VM to match the number of threads that the application can use. This can help avoid CPU contention and co-stop issues that may arise from having too many vCPUs relative to the number of physical cores on the host5.
Upgrade the physical CPU on the host to a faster or newer model that can provide higher clock speed and performance for the single core that the application uses.
Optimize the application code or configuration to make it more efficient or multi-threaded, if possible. This can help the application take advantage of multiple cores and improve its performance.

PowerShell is a scripting language and a command-line shell that uses commands that start with sec- to perform security-related tasks. For example, sec-edit is a command that edits security policies, sec-logon is a command that manages logon sessions, and sec-policy is a command that applies security templates. Verified References: [PowerShell security commands], [Security policy]

The most likely reasons why the technician is unable to access a server's package repository internally or externally are that the external firewall is blocking access and that the default gateway is incorrect.
A package repository is a source of software packages that can be installed or updated on a server using a package manager tool. A package repository can be accessed over a network using a URL or an IP address.
However, if there are any network issues or misconfigurations, the access to the package repository can be blocked or failed.
An external firewall is a device or software that controls the incoming and outgoing network traffic based on predefined rules or policies.
An external firewall can block access to a package repository if it does not allow traffic on certain ports or protocols that are used by the package manager tool.
A default gateway is a device or address that routes network traffic from one network to another network.
A default gateway can be incorrect if it does not match the actual device or address that connects the server's network to other networks, such as the internet.
An incorrect default gateway can prevent the server from reaching the package repository over other networks.

Blanking panels are metal or plastic plates that are installed in the empty spaces of a rack to prevent hot air from recirculating back to the front of the rack. This can improve the airflow and cooling efficiency of the rack and reduce the heat generated by the servers. Verified References: [Blanking panel], [Rack cooling]

SSH port 22 for secure remote access and 443 is https for encrypted website browsing.