Why dont you get yourself one of supported sailfish os phones and install sailfish?
It works for me without issues for 2 years now and I can run android apps in lxc container (without them having access to any relevant data).
Sailfish gives a Linux experience. It is mostly, but not completely, FOSS. It is more privacy oriented than both main platforms from Google and Apple. For me it is a good compromise for now. For you, that might be different.
Actually from all my experience, as a long time rom cooker, who was running angstrom on blueangel, before the android existed, sailfish is our best bet to dethrone google and apple. A small one, but there is at least a chance.
Everything else is lagging too far behind on the verge of useless, as PinePhone has demonstrated.
Just an example, my xperia 10 II phone is running sailfish without any hardware deficiencies, f.i.: bluetooth and fingerprint reader are running fine, working as expected. Battery life is excellent. There are maybe a few android ROM projects that can brag about that and quite frankly they are not very far from the AOSP.