Look into SuperNote or OnyxBoox devices, they work quite good even if there is a learning curve.

Cosmoteer is high up there. Also BapBap is fun

Does it matter? Seems like you have the time with all your procrastinating. Just try it for month.

You can create communities and spread the word about their existence.

In the last 2 years a lot has happened. I suggest you try PopOS or Fedora. I switched from Windows to PopOS 2 years ago on my main PC. There is a learning curve but if you want to know how something works a search of “how to do thing PopOS” or “how to do thing Ubuntu” gives quick results. PopOS is similar to Ubuntu in many ways but way nicer in others.

What about MS Office do you need? Are you a poweruser that is very much bound by the interface due to habit? Otherwise check out OnlyOffice, it works with docx xlsx etc natively. You can also try it on windows first.

I guess it is up to the person creating the channel. There are “Spaces” and “Rooms”. Spaces are the equivalent of discord “servers”. But rooms can also be created outside of a space, making them similar to a group in Telegram/WhatsApp.

In Element (an app that uses Matrix protocol) you can basically organize yourself as in Discord. Rooms/Servers with subchannels that you can invite people to and distribute admin/mod rights.