You might check out this thread, especially that first post about the open letter.

https://news.ycombinator.com/item?id=33749757

I homelab to study and practice, and I switched around 1.19. It’s been very smooth for me. Literally just had to change the docker image I was using.

Not sure about the rest of those, but Obsidian isn’t OS either.

I think Rocketchat is what you’re looking for.

Now just make sure to “keep it secret, keep it safe” by not telling anyone what it is. Still a good chance you could be hacked, but it will keep you somewhat safer.