Thanks for keeping us update on the situation / progress.
AV's deleting game executables is certainly far from unheard of (hence why it's one of the clean reinstall steps). But can't say I've heard of an AV deleting all game executables before. And is it just Steam games? (have any games on GoG you can test?) Or does is it affecting all executables? (have your tried running anything else? Media software, image editors, office programs etc. I assume your browser's executable is still working fine, unless you're posting via another device).
And is Malwarebytes a recent addition or have you been using it for a while? If it's recent then maybe you used a rogue installer that's caused it to screw up somehow (IIRC the official CCleaner installer got hacked a while back and hijacked to install a Trojan alongside CC. That's less likely to have happened to Malwarebytes but possible with rogue installer. But if you've been using it a while then this longshot theory doesn't fit).
AV's deleting game executables is certainly far from unheard of (hence why it's one of the clean reinstall steps). But can't say I've heard of an AV deleting all game executables before. And is it just Steam games? (have any games on GoG you can test?) Or does is it affecting all executables? (have your tried running anything else? Media software, image editors, office programs etc. I assume your browser's executable is still working fine, unless you're posting via another device).
And is Malwarebytes a recent addition or have you been using it for a while? If it's recent then maybe you used a rogue installer that's caused it to screw up somehow (IIRC the official CCleaner installer got hacked a while back and hijacked to install a Trojan alongside CC. That's less likely to have happened to Malwarebytes but possible with rogue installer. But if you've been using it a while then this longshot theory doesn't fit).