Rouge sysadmin and supreme overlord of GravityWell.xYz.
For a private screen you can use a web based solution like mirotalk or jitsi. Pretty much all web browsers support screenshare via an extension these days so its mostly just a matter of finding a server with low latency (or running your own)
I tend to stream directly to peertube so thats what i was thinking of for obs but its true that obs isnt ideal for smaller private sessions.
This attitude is exactly why you and most people will be continuing to repeate this cycle of enshittification every 5 years or so.
You went from using multiple apps to a big clunky web browser that only connects to one service and you trust that service not to screw you over one day.
This is why we cant have nice things.
Stoat would be nice except its still a silo, you can self host your own silo but it doesnt federate, cant even use their offical app with self hosted instances. Upryzing seems like it might be going in a good direction but too early to know for sure.
Xmpp or matrix are the only truely decentralized options and neither is up for doing all the tasks discord gets used for.
The problem is many folks dont grasp the concept of doing one thing well over doing lots of things just sort of okay.
My suggestion to friends is figure out what discord features you actually care about and find apps that do those things. Muble for audio, obs to screen share, xmpp or matrix to chat, etc.
What sort of things are people trying to screen share on discord? Are you watching a movie together, playing a game, or ???