I had the same desease for a long time.
The bug is hardware : it's due to a bad type choice on a decoupling capacitor used on GPU motherboard part
But good news, you don't have to replace the motherboard
Julian Poidevin sent me this:
Hi, I created a software to automatically correct this issue, you can download it on github, it's free :
https://github.com/julian-poidevin/MBPMid2010_GPUFix
Install it. Password requested is your login session password because that software must change SIP (System Integrity Protection) to force GPU to take medium speed always. For more info read FAQ in poidevin site.
Now my MBP 15 mid2010 is working fine
If you have installed GFxCardStatus let it in dynamic mode.
Any time you update MacOs you must do a reinstallation of the poidevin fix again.
That fix was developed based on fabioroberto investigation
https://forums.macrumors.com/threads/gpu-kernel-panic-in-mid-2010-whats-the-best-fix.1890097/
see post #20