The cause of the “Rendering device lost” can be the GPU even if it works with other software. I experienced consistent and very frequent “Rendering device lost” errors (every few minutes) with one of the strongest RTX 2080 Super GPUs from one of the most popular brands. The card had issues only with OW. Replacing it to any of the other RTX 2080 cards I had access to eliminated the problem instantly. It wasn’t a driver error or similar, only the GPU was different. All cards were under about 60% load (Ultra settings) and everything was very far from overheating. My current RTX 2080 Super card (that works perfectly with OW) has some factory OC but not as aggressive as the problematic card.
If your PC crashes then the reason can be overheat even if your sensors don’t read any suspiciously high values. I experienced PC crashes about 2 years ago (it was unpredictable, sometimes every 10 minutes, sometimes once per day) and buying one of the biggest CPU coolers solved my problem. (The original cooler was the same brand - Noctua - but a smaller model.) I use only a hexa-core i5 8600k @3.6GHz without OC, not too beefy but still more than enough for the games I play. It can heat up within a split second when something starts using all 6 cores. It’s probably worse with an 8-core i9. Before the CPU cooler upgrade I tried to solve the crash issues with a lot of other things (reassembling the PC, different/stronger PSUs, etc…).
BTW, why are you using ITX? I’m a huge fan of small minimal design machines but in case of strong PCs (gaming, data science, etc…) going for ATX (perhaps EATX) is much more practical. You have access to a wider range of motherboards, cooling is significantly easier and you are less likely to have strict limits on graphics card size (you can also have 2 GPUs if needed). A modern ATX case (that doesn’t leave room for ancient DVD-drives, floppy drives, HDDs, and similar) can be very small. What I’m using is a good example for a modern small ATX case without much wasted space inside (Fractal Design Define C) and I upgraded to this from the micro-ATX version of the same model that was only 4 centimetres shorter in height! Saving 4cm wasn’t worth being limited to micro-ATX motherboards. There are much more ATX boards available with better VRMs.