The only thing I would change is your backup drive. Linux can write to NTFS without issues. You'd be better off with 2 TB instead of 2x1TB.
I would get rid of all the HDDs for games as they are too slow. Verifying files under steam or other clients is so slow compared to SSDs. (If you can afford it of course, otherwise it's fine)
There isn't anything else wrong per-se. Except for still having windows installed π€£. Proton (wine) via steam or lutris, solves 99% of all issues with running games on linux. (except for Anti-Cheat games like valorant).