Ever since moving to 1.17 multiplayer has had major lags. Currently two players in multiplayer mode rarely lags. Three players lags approximately 75% of the time. Four players make the lag impossible to use. 1.16 was fully functional in four player multiplayer mode. 

We've trying multiple different settings easy/hard, cheats/no cheats, nothing seems to make a difference.

Internet speeds are great 10+Mbps down and 4+Mbps up as reported from the switch.