I hated going through 5a the first time, it made me want to quit playing the game too (out of fear/frustration/feelings of futility) but I think it's intentional given what the chapter is about, and to that end it's done really fucking well.
Replaying the game for speedruns and stuff though, 5a is really fun (esp with wavedashing)
Honestly chapter 3 was way worse to me at first. I hate those red dustbunny things and I swear they made the timing specifically so that I would constantly run into them and I hate it.