Had a similar issue with Valhalla; crashes since updating to 1.1.2 rendering it unplayable. This with low temperatures, stable voltages and no other software having any problem.
Tried the tips found at these forums; checking the integrity of the OS, trying different graphics drivers, changing the virtual memory amount, emptying caches -nothing fixed it.
Eventually I decided to update the NZXT CAM software monitoring my X62 cooler, from 3.7.4 to the latest stable version, 4.20. Since then I've been running AC:V crash free for some 15 hours.
CAM is notoriously buggy but has not so far, in my experience, been a problem running other software. Despite this, anyone running an old version should consider updating it if they have a problem running AC:V.

Good luck.

Win10Pro 2020H2
R2700X
Asus1080TI
16GB 3200MHz