Chat must be routed with Omni-Channel in Lightning Experience because Omni-Channel is the only way to route chats to agents in Lightning Experience1. Chat can only be added to Console navigation Lightning apps because Chat is a console app feature and requires a console app with a console navigation style2.
References: 1 https://help.salesforce.com/s/articleView?id=sf.live_agent_chat_omnichannel.
htm&type=5 2 https://help.salesforce.com/s/articleView?id=sf.live_agent_chat_app.htm&type=5

A permission set is a collection of settings and permissions that can extend users' functional access without changing their profiles. By creating a permission set with view All on Accounts and assigning it to the service and sales managers, an administrator can grant them access to all account records in their org without modifying their existing profiles. References: https://help.salesforce.com/s/articleView?id=sf.
users_permissionsets.htm&type=5

One possible cause of unexpected changes to record values is having multiple automation tools that update the same field on the same object. This can create conflicts and overwrite each other's values. To resolve this issue, the administrator should consolidate automation tools and use only one tool per object and field combination. This can help avoid confusion and ensure consistent results. References:
https://help.salesforce.com/s/articleView?id=sf.process_which_tool.htm&type=5
https://trailhead.salesforce.com/en/content/learn/modules/business_process_automation/automation_considerations

An after save flow is a type of flow that runs in the background after a record is saved and performs actions based on the record data or changes. An after save flow does not require user input or interaction and can be triggered by a record-triggered flow element or by an Apex trigger. In this case, you can create an after save flow that runs when a case record is updated and delivers status update email to customers based on certain criteria or conditions. References: https://help.salesforce.com/s/articleView?id=sf.flow_trigger_types.
htm&type=5 https://help.salesforce.com/s/articleView?id=sf.flow_concepts_trigger.htm&type=5

Public groups let you share records with a set of users defined by criteria such as role, profile, or individual users. You can use public groups as recipients for email alerts in workflow rules or process builder.
References: https://trailhead.salesforce.com/en/content/learn/modules
/administration_essentials_for_new_admins_in_lightning_experience
/administration_essentials_for_new_admins_in_lightning_experience_security_sharing