I also got a bsod.
As soon as my friend and I expanded our base, added two smelters and two kilns and entered the copper and bronze age my performance dropped hard and the system went to BSOD.
Never happens on this computer. Clearly unusual.

I uploaded my world save state to discord and he downloaded the files to his computer and hosted, as his PC is beefier than mine. Within an hour we were starting to get the same type of experience. Lag. Not seeing updated locations of one another on screen. etc.

At one point I saw his character running midair above the back fence of our property for a solid 10 seconds. I said wtf are you doing in your game, and he said he had hopped the fence 20 seconds before that to go chop trees.

So for god knows how long, prob a solid 30+ seconds, he showed in my game as pulling an airwalk stunt over the property. It just becomes unplayable. Seeing him swinging at a mob in front of me, but the mob is dying 30 feet away because that is where he actually is standing.

Using an ultimate near one another to share the buff and realizing we were 'near' each other on screen but in reality, too far apart for it to work.

Game needs some tweaks.