Right after my Minecraft Bedrock Edition client was updated to version 1.16.40 hotfix I began experiencing mouse input lags, so noticeable that it renders the game unplayable.
It occurs after I create or enter a world. Sometimes it takes up to 2 to 3 minutes after the chunks are apparently done rendering to normalize, only to start lagging again, without having to leave the loaded area.
My system monitor reports 100% CPU usage from Minecraft after I start playing a world, with not much GPU processing/memory use. The RAM memory footprint remains stable also, only the CPU usage goes skyhigh.
System Info and screenshots of the CPU usage before and after a world is entered are included.