Interesting this was mentioned. I was wondering whether to try a class rather than do it on myself. Are you taking these at a local university or online?
It's just a few courses TBH: one for programming (can skip if already know), one for comp arch, one for data structure and you are done with the basics (drop in either a discrete math course if you have no exposure to it, which I do, or a computer language theory class if you want to do compiler). You can then take advanced courses e.g. Operating system or Compiler theories.
I'm always thinking about going that route, saving some $$$ yet learn more than from mediocre local universities. Tried a few times but never get past the data structure course.
Ping me if you want to do it altogether. It's probably easier when studying in a group.
edit Just realized you are a backend developer so you are probably better than me. I mean you can probably skip more courses :)
I'll let you know. If I decide to go down the study group route, I'll ping you. I have already taken a data structures course, but nothing close to Operating Systems or Compiler Theory.