Flanagan no problem! I know you already did a factory reset but I insist you do it again, now that your phone got a new software update. I know it’s a “pain in the ass” to setup everything again but trust me, if things were already behaving in a strange way before the update, they will be harder to fix now.
I had a problem with the “smart charging mode”, spent two weeks trading emails with Nothing support (they were impeccable), testing changing dozens of things including charger and cable, etc. Only after I did a second factory reset which I was almost sure that it wouldn’t work, took time to setup each app with patience and didn’t mess with any permissions, then my problem was fixed.
I don’t know if you use any apps outside of the Play Store like direct downloads or just uncertified apps. If you want to share the name of the apps that are giving you trouble I can try to help you further. No promises but I will try to help you to the best of my ability.
Um abraço de Portugal