I've happily used LineageOS without gapps for years across several OnePlus devices. If I ever need a new phone I check their supported devices list to pick, and the stock ROM on my new device gets overwritten the day it arrives. Currently using a OnePlus 8T. When I move on from this device as my primary someday, I may put postmarketOS on it to extend its usefulness.

Don't forget Anom. (A cautionary tale.) https://darknetdiaries.com/episode/146/

I've used Lineage. I'd say it's worth a look, yes. I got a Pixel for Graphene, though.