I used to run CyanogenMod/LineageOS on my older phones, but since my S8, I’ve been using stock ROMs. Honestly not even sure a custom ROM exists for the S21. I’d love to make the switch if it does, however I know Google Wallet (Google Pay at the time) had a huge issue with custom firmware/ROMs and I don’t imagine it’s gotten any better over the years.
“Friendly fire is on”
“Ok” Walks through fire
“I THOUGHT YOU SAID IT WAS FRIENDLY!”