Just to let you know, I've been playing around with options and can sometimes get it stable.
I almost feel like it's something to do with some or another particle effect...
But I can't say that.
Regardless, I've managed to get it stable enough - DX12 version, 60FPS, full rendering -
That I've been able to play a few matches, and it's a pity I can't give any other advice because it's absolutely great.
Didn't realise how much of a maze-running procedural hole was in my heart until the last few days, haha.
And, y'know... If the Widow wants to get re-married, aye. Yeah. Definitely.
More seriously, don't have any other big theories.
Will try to keep an eye on your work and support it later so that when you release next, I can see if I can pinpoint anything.
I'll post here if I figure out what it is, even if the end result is 'yep, just a hardware issue' so you can cross it off the list.
Best!