Feeling Heavy about the System's rules

I've been DMing this system on & off for the past year. I'm scheduling my 15th session in a homebrew campaign I run for myself and 4 other friends. However I'm running into an issue. Even after all this time, I feel like the amount of rules in this system weighs heavy on my head. I can understand that the books are only so big because there's a lot of player options in them like races and classes.

How can I still feel overloaded? I build the encounters based on the builder, I pick out magic items and treasure(I still have trouble with this), I make the sessions. Am I just overreacting? My players love our game, they get super excited for each session but I always feel like I'm wrangling a Tarrasque sized system to run the game, PF2e has a lot of dials and whistles to it. I want to get more comfortable.

Anyone have advice?

**Edit**
Thank you everyone who answered, the post wasn't up for long and you all have been super supportive. This is another reason why I want to stick with this system. This community is amazing. Thank you! :>