Thank you for your kind considerations, @generix.
After today’s formatting attempt (from 18.04.4 LTS to 19.10) and BIOS update (4.00 to 4.30), some settings I’ve been using were restored to default. I’ve performed steps 1-5 (list above) again just to guarantee. After the BIOS update, I’ve played a DoTA2 match and after about 30-40 minutes my PC froze again. In complete despair, I turned my PC off, opened its cover, disconnected, and connected my GPU. Since then I’m running one instance of my deep learning model and the freeze did not happen (but I think it’s a happy coincidence). I’ll let it be for today to see if something has changed at all, but if not I’ll install Ubuntu 20.04. Since this version have a new kernel I think the chances of improving my situation are higher. When formatting I’m keeping my /home folder. Do you think it can be a problem in this case since many configuration files are being kept?
About your workaround, what frequency do you suggest? sudo nvidia-smi -lgc 1900?