did you ever use jitsi? its not a chat platform, but one for video calls. it supports screen sharing and its very good.

matrix used to use jitsi for group calls. I don’t know what does it use now as a transition to an in house service has been in the works for a few years now, and element call just now starts to get mature enough, but I’m almost sure you can do screen sharing right now too. but try to check how usable it is before you try to get your friends to use it. if it doesn’t work well, they may not accept your advice (as easily) in the future to switch chat providers