Honestly, for AOSP, there are so many options. But if you don't mind having not much customization, I would go with arrowos : constant update, and stable. But other ROMs maybe better (most likely), depending on what you want and need.I'm having the same "issue" as the OP, currently i'm on LineageOS and everything runs just fine but i want to try something else, i just don't know which one to pick. I know "best" is subjective but i'm still curious.
Also, which gapps would you guys suggest, i only use gmail, maps, fit and the store.