Hello!
i am not happy with giving money to zoom but i will not oppose it because i think it’s important that the tools work to do your job and you are happy. just one thing: the subscription should have a time limit. after one year we need to vote again.
having said that, i don’t agree with the critique, I think Jitsi is a great tool for what we need
i am going to put an analogy with a public swimming pool 
. if there are a lot of people in the pool, the experience sucks. you can swim very slow. better to go to another pool. Jitsi is another public good. somebody out there is freely giving you access to computer resources. if there are a lot of people at the same time running the public good (the jitsi instance) then it’s slow. better to go to another Jitsi instance. the trick here is to have a couple of instances back up. so you move everyone to another link . it sounds complicated but it is not. just send another link in signal.
this is not a jitsi problem. jitsi will ask permission to your browser. you need to agree to allow jitsi to share micro and video
i don’t know what you mean by this. screensharing works marvelous in my own experience