I just want to add my experience as well.
Since updating to 1.16.20 on the Nintendo Switch I've encountered a lot of freezing. Trying to play splitscreen multiplayer on my realm.
While playing splitscreen on a realm, after about an hour the game froze while we were both just walking around our base. I was able to hit the home button and tell the switch to close the game. After a few minutes the switch gave the message that there was an error and had to close the game.
Then, after restarting the game and joining the realm the game froze again as the second player tried to join splitscreen. I was able to hit the home button again and tell the switch to close the game - at this point the switch system completely froze and I had to hold the power button to turn it off and back on.
We tried a third and fourth time to both get onto the realm, once again unable to get two players to join splitscreen without it freezing and requiring me to hold down the power button to turn the machine off and on again.
A fifth attempt saw us both able to get into the realm and play. We were both able to save and quit. Back at the Minecraft menu screen I pressed the home button and told the switch to close the game - at this point the switch completely froze again and I had to hold the power button down to turn it off.
So I've had the game/switch freeze when trying to close the game, and when trying to get a second player to join splitscreen on my realm.
Same problem Minecraft Server Version 1.5.2
This has happened to me a couple of times now on a bedrock realm playing on the Nintendo Switch. Both times there were more than one player on the realm at the time.
First time I travelled from a nether portal in the nether to the overworld. Instead of exiting at my corresponding overworld nether portal, as I have done numerous times before, it sent me to a random location a few thousand blocks west over an ocean and I had to swim all the way back. Oddly, at the time I could not see the nether portal, obsidian, that the game created in this new location, but later another player spotted it floating up in the air above the ocean.
Second time I travelled from a nether portal in the overworld to the nether. Instead of exiting at the corresponding nether portal in the nether, as I have done numerous times before, it sent me to a random location east about 10,000 blocks away. This time I died trying to find a way home. Oddly, again, I could not see the nether portal obsidian that the game created in this new random location. However, as I started to mine a tunnel, the invisible obsidian blocks would become visible, one at a time, as I mined out a block of netherack adjacent to it.