Nope, to be senior you have to be doing it as a job for a few years. Programming alone is several league different from working with a team. And lastly to be good at something you have to actively practice (build stuff), not just read, read, read whatever ressources you use.
I'm an accountant. Have been programming for years, paid college by hacking games and selling bots. Covid19 quarantine gave me the time to dive back in and actually relearning programming correctly, and rekindled my passion for it.
It's actually harder to find a remote job because if I work full time for someone else I will not settle for 500 and probably will not accept anything paying less that my job now.
It is not, it depends on what you do, what problem you want to solve and so on. You noticed it yourself, for example for game dev windows is just plain better. These OS fights on which one is better are just nonsense.
As an European, this question doesn't even deserved to be asked, of course it should. Not just higher education, but at all level. More educated population is always better for any country, so education should be accessible for anyone and not hidden behind paywalls. Education and Healthcare should be where most of the tax money goes.