I had similar problems with my last Zotac card. Buggiest card I've ever had. It was the 3070 twin edge. It was an amazing deal on amazon, same price as a used card! I couldn't believe it... but perhaps that was for a reason.
Anyway, it worked fine for about a week. Then I started getting stutters. A driver reinstall always fixed them but they would always come back shortly.
Then later on I started getting artifacts, tbf, I was running an emulator, so it is possible it wasn't actually the card but it was a game I have played on other cards so... I have a feeling it was the card.
Then it would just decide to stop outputting video at random. A restart would fix it, but after the second time it happened I gave up and returned the damn thing since this all happened within 30 days.
I'm not saying I'm swearing off Zotac as I have had fine Zotac cards before, but if the price was the same I would probably pick something else first.
Anyway sorry I don't know how to help you other than suggesting an rma or sending to a repair place if thats not an option ( which it sounds like its not). Good luck and sorry I wasn't much help.
EDIT: Check out this guy, he's a magician. He will do things most repair shops will not. I don't know what his prices are, but given the amount of time he puts in and the equipment he uses, I can't imagine its cheap.
Contact me on DISCORD https://discord.gg/krzHbYpUMy Or email me at tony@northwestrepair.com (ignore automatic reply) Tools, schematics, boardview files etc are available here https://drive.google.com/drive/folders/12XQpmc9tLwlRQjlo3Mn_XwKlVcV8XYGI?usp=sharing Buy me a candy at...
www.youtube.com