BIG takeaway:
Timeshift.
Treat your journey like a video game in ‘hard mode’. Save your progress often!
Before embarking on a new quest or mission, save your current state with Timeshift, so if you end up going down some rabbithole, trying a solution you found on some blog-post that doesn’t work, or is outdated, or was for a different distribution, or you mistyped one of the fifty commands or whatever, you can safely return to the state your system was in before you started.
Trust me on this.