Earlier quoted context omitted.
I've seen a company during WFH let a laid off employee (who asked) keep their access for an hour, to post a goodbye message. It's not good practice for all situations -- you need some trust, despite the stressful situation, when people tend to show character and weaknesses -- but in this case, it worked out. The departing employee posted a message of encouragement to the remaining people. Kind words and contact info…
You can get nearly the same result with less trust: let the employee draft a goodbye message and have the boss (or so) forward that to the other employees.
The company letting a manager relay a message, with any censoring, is certainly better than the person having no way to get their contact info to people, and they might also say something nice for morale.