Minecraft v 1.21.06 Crashes multiple times in 1 hour

Hello, 

during last 3 days, while coding with Minecraft I experienced 2 different problems on teacher PC (windows 11).

The first is that the mouse freeze randomly. While playing the mouse stop moving and I could only move the player with the keyboard. This happened multiple time is 1 hour.

The second occurred while I teaching in multiplayer mode. We were coding in a flat world and Minecraft crashed and all the students were disconnected. This happened  3 times in 1 hour.

What can I do to solve these problems?

Thank you