All Shared activation cares about is with what user account you have activated office, now if you create a dedicated single account and let different users use the account to activate office; i think you should be good. If you are logging into the terminal server with an account which is synchronized to office 365, you might have to play around with office apps a bit so that it doesnt attempt activation using the computer account you are logged in with. (Thinking out loud).
Also, shared activation doesn't actually count as an installation instance.
From the article you shared :
Activation limitsNormally, users can install and activate Microsoft 365 Apps only on a limited number of devices, such as 5 PCs. Using Microsoft 365 Apps with shared computer activation enabled doesn't count against that limit.
Microsoft allows a single user to activate Microsoft 365 Apps on a reasonable number of shared computers in a given time period. The user gets an error message in the unlikely event the limit is exceeded.