Throttling is one thing that can cause high kernel_task usage, but you can also run ‘pmset -g thermlog’ to verify whether it’s actually due to throttling/cooling issues.

My 16 inch throttles so hard. kernel task at over a 1000% (thousand%) CPU. Scheduler limit under 30/100. This is just painful

I have the same issue. How do you know if it's throttling and if so what is the action to take? My fairly recent Mac is completely failing at doing video, while my 2012 I dragged out of storage has no issue.

The command’s output is pretty straightforward. It tells you the percentage of CPU you have available to use. Leave it running and try something super intensive. It’s much easier to get my Intel MBA to throttle than my work-provided 16” MBP.