While AA is constantly updated to be optimized for current OS, it should still work for older units that no longer have updates offered. That being said, electronics are wonky and one thing can impact so many other areas. Short of trying another phone to verify it isn't the head unit's fault, you may be needing to upgrade to a newer phone if a factory reset won't fix it.
I have a wonky problem with my HP printer where I can't scan from it to my phone, so anytime I want to scan I have to pull my older 4a5g out which will accept scan. Gave up trying to figure 6 and 6 pros out, and I have had 5 Pixels and pretty handy with software. Sometimes you just have to admit defeat. FYI, 7a is coming out in May and will have updated camera sensor, but I have seen some crazy deals in 7 and 7 Pro and they are great phones
Good luck.