There's so many different fixes. In the end I tried them all, but I think the tipping point for me was disabling all in-game overlays like Shadow play, Steam, Ubisoft Connect. In fact for Steam and the EA app, I closed them completely. I've played for about a week with no crashes so far.

The rest of the fixes have running are stuff look running in admin, disabling the exploit protection for the game exe, updating the anti-cheat, running in DX11, lowering fog quality from high. If you manage to find a list of stuff to fix Div2 crashes, there's a solid chance I've tried them all.