I run e/OS on a FP5. I ran e/OS on a Essential PH-1 before and going back to a phone with Google installed just didn't sit right with me. I did not feel like I could trust the device even after trying to toggle as much of the creepy spying off. As if there's still someone probably looking over your shoulder because you configured something wrong.

It is not perfect, but it is easy to use and full-featured. All regular apps feel great and battery life is good. I still use specific Google services (such as the calendar for work) but no specific Google apps. I guess Maps is the biggest challenge now but alternatives are good enough to get around with.

You can run Android apps. Not sure about payed Android apps. I try to install FOSS apps through the integrated f-droid store if they're available there. Installing app store apps sometimes fails because Google blocked the installer. I could install everything so far when needed (including banking apps and specific apps for the vacuum cleaner and such). Sometimes the Android app store apps don't update for a while and I don't notice.

I don't use Murena's services but self-host Nextcloud. Based on the information they send I think they're doing a great job for their size.

I flashed the FP5 myself with a beta of e/OS when it was just out because the other phone was broken and (again) I did not feel right with the spying demon in my pocket with native Android. You could flash your device too.

It's comfortable on this side. If you have further specific questions, shoot.