I think Linux phones are something for enthusiasts still. If you found Graphene to have rough edges it’s not going to be much better in the world of Linux phones.

Android apps can run through a compatibility layer called Waydroid. Allegedly it works pretty well, but it’s not super convenient.

Personally I put my bets on a Fairphone 5. It’s currently running /e/OS, which is a French open source degoogle Android. Open source development for the Fairphone 5 is very active. If I were to install something closer to proper Linux on it now I would go for Ubuntu Touch (which uses the kernel from Android rather than mainline), but it seems like it’s also moving quickly towards supporting mainline Linux and PostmarketOS in a good way.

The phone should last a while as it’s repairable, and if they’re not ready for Linux phones it makes it easy to install /e/OS to get back to degoogled Android. And it has a large community of users/developers. So I think it’s a good option.

Then again, if the goal is a fully FOSS phone for casual users it’s possible waiting a little longer is not the worst idea.