Debian is better as a server host. Ubuntu is not easier for a server for anything except initial installation but you’ve already done that once with Debian so you’ll be fine. Only reason to use Ubuntu is if you want core software updates every 6 months and for this purpose you don’t. And can still have the option for newer software in select cases using containers.

FOSS has always been political. And usually fairly reactionary.

I recommend using pen and paper and then digitizing later, assuming this is for notes. It will help you internalize the lecture or reading better in the moment and the act of digitizing your notes will reinforce your knowledge and provide you with better material for tests.

I think the only digital option that could come close to this would be an e-ink tablet but those kind of suck. Better to spend $50 on paper and pens than $500 on a tablet that isn’t as good for the purpose.