Not really, my only period of interaction with the language started and ended in high school. I’m sure you’ll find tonnes of recommendations in language-learning communities on the internet though.

Most privacy-friendly way would probably be using a textbook.

I’ve only ever used kdenlive and it was adequate for my needs I use it only for very trivial editing tasks tho, so I can’t say about anything complex

fucked up situation, man wish you all the best