Ever since the patch came on that made crossplay possible about 1/3 of my matches are ruined by massive lag that makes me unable to focus fire, and generally make the game unenjoyable. Would love to know if this is just me, or of it is a general issue that the connection between players can be so garbage?

The simple fact you stated yourself saying that only 1/3 of games are laggy proves that's not general.
Chances are it's a matter of geographically remote players.

I'm located in Denmark, so just North of Germany. But might be an extreme case due to me playing at odd hours. Well could be general issue that the matchmaking would match people with horrid connection to each others at a whim. and "only" 1/3 of game is a high number all things considered. That's 1/3 of the games being where i just have to surrender at start as i really don't care to play them.

Were just suprised to get almost instantly matched up upon queue to then enter games that were bordering on unplayable. As you wouldn't expect the matchmaking to crete such a match without first waiting some time while looking for games with playes in closer proximity.