I use MS Teams for online courses for something like 10-20 people. I find it pretty slow and clunky to change settings and it is painfully obvious that it was made for large businesses and not for my case.

Beside that, it is Microsoft and American. What are the best European alternatives for what I use it for?

I'd love to self-host, but I find VPS with the specs required to be too expensive for me atm.