(I am holding out hope for the phone that the GrapheneOS project is planning to make.)
I bought a PinePhone, and after a few too many show-stopping issues (not being able to receive a call for a scheduled job interview was the last straw), I went back to using LineageOS without gapps. I'm not a developer either, just a fairly technical user, so when the device wasn't working, all I could do was report bugs, and things weren't improving fast enough. I haven't checked on progress in a while now. postmarketOS seemed like the one to follow, and they do also support some beefier devices like the OnePlus 6T, but then you'd miss out on the PinePhone's ability to easily remove the battery and to boot off the SD card in addition to eMMC.
I also felt a bit bait-and-switched that the PinePhone Pro came out not too long after the original and then everyone seemed to switch to that one. It reminded me of the awful Gemini PDA and how quickly they rushed out a successor without fixing any problems.
I was just saying that you can make the problem more narrow by not trying to support every device out there. Start small and pick your battles (which probably means using AOSP and using sandboxed AOSP).
I think the main issue of many previous attempts was what typically happens in the FLOSS community: there are N attempts rather than one coordinated attempt (Ubuntu Touch, Plasma Mobile, PostmarketOS, PureOS, etc.) and everybody is targeting different hardware. It's similar to how the Linux desktop got fragmented, though it's even more problematic for mobile, since the usage is probably 1/1000th of Linux desktop usage.
When was it? There are no complains from people daily driving both phones in the last couple of years AFAIK.