Hey i’m not tech support but i got a few things you could try:
first you wanna ensure that the problem only occurs with overwatch, if you have any other 3d applications that behave the same you can be sure its not related to OW.
if every other game you have works fine, check your other drivers, not just the GPU drivers… if you do not know how to do this manually there are various programs that do it automatically like IObit driver booster. ( which has a free version )
Also you could try using DDU to reinstall your GPU, this ensures nothing of previous driver installations is left behind. ( free program, google it )
If you have any over clocks, try disabling them and try again, especially GPU oc has been known to cause problems with OW… a friend of mine crashed nearly every game but when he disabled his oc it worked fine.
If none of that works, you could use HWmonitor to see what exactly happends to your hardware while you play, perhaps something is overheating?
If something is overheating, clean out all the dust from your pc, dust that gets heated can form something that is refered to as artifacts, and those artifacts are basically dust that gets crusty and is even able to block your fans from spinning, thus overheating your hardware.
Important sidenote, when you clean out your pc, ensure you hold your fans so that they do not spin in opposite direction as this can severely damage your fans.
If all this fails and you are sure its related to your pc hardware and not a software issue you could try resetting your BIOS to default, perhaps even do a bios update if you have never done this.
Also its good to try and remember when it worked without issues last and what you have changed in the meantime. perhaps you will suddenly realize you changed something in your system/hardware and simply reversing this change will fix your issues.
Hope this helps.