Today 10 years ago I went to Poland to buy a Phone with pre installed #Firefox OS on. The Phone was a Alcatel One, so very shitty. Two years later I installed Firefox OS on my Nexus 5 instead.
It was a very good concept, but sadly rolled out on too shitty hardware so it never caught on.
Up for GrapheneOS! It's weird that to have a degoogled phone you need to buy Google's ones but so far is the smoothest ungoogled experience I had (I tried LineageOS without GApps, LineageOS with microG and /e/ OS in case you were wondering) Also, since google services are installed in a sandbox you could even have a profile where you have them and all apps that require Google Play separated from the profile you normally use which is pretty cool (even if I'm using them sandboxed just with the permissions I need on my primary profile atm)