The automatic enrollment of all upgraded servers (including auto-updated) into the starter enterprise subscription with a limit of 25 users was a bad decision, not thought out at all.
Almost all users of open source, and Rocket.chat in particular, are especially sensitive about privacy and consent.
Anyway, the Community Edition users won't have the user number limitation, which is now clear. Phew.
As for chat clients, we had Rocketchat with Omnichannel some time ago but abandoned it.
Since our students were already on Discord, We moved to Discord as well. The interface takes some time to get used to though.