Unable to Play with 3+ Players
Ever since the 1.21 update came to Nintendo Switch it has been impossible to play multiplayer with three or more players. When a third player joins the world, the game essentially freezes - you can still move around, but nothing loads. After a few minutes, the non-host players are kicked and any movement/actions done after the freeze are not saved.
I have submitted two technical support tickets about this, they were not able to assist and sent me here to report the bug. This is not a network or hardware issue. I believe it is related to bug MCPE-187710.