If I’m not mistaken, memory editing may be a valid method.
For example using CheatEngine on Windows or on Linux there is scanmem. Many other tools may exist for memory editing also, but one could easily Dockerize the TeamSpeak server, memory edit values on the server and it could lock/freeze values of user count etc
This could be totally automated using Python or other tools as well. Hope this helps! Let me know if you have questions
Alternative to this you would want to MITM the server connection as it reports back statistics and either modify the requests or forge them altogether. It’s noteworthy TeamSpeak has hardened from this somewhat and may require a TS3-like protocol to touch a live server port as a ping of sorts to make sure a server is properly running. Some of this is more or less guesswork. You are welcome to test though