Severe lag and broken controls — camera freezes, character moves by itself

The game is almost unplayable because of extreme lag and control issues.
My character sometimes moves on its own, the camera randomly freezes, and when I try to move the camera left or right, it instantly breaks or destroys blocks around me (even though I didn’t click anything).

In multiplayer, it gets even worse — all players are lagging badly, movements are delayed, and basic actions like mining or placing blocks don’t work properly.