you could have a defect controller or a defect nvme.
I bought a new laptop some years ago, I suspected the nvme to be defect, did a waranty claim, received the nvme and realized the controller was actually corrupted.
is this a notebook? Do you have a second nvme slot on the board?
I looked a little bit into the problem. I found an issue. baloo_file is continously writing (do not know why not reading) to the disk with ~300 M/s (see iotop output).
This could be the main reason for the issue. Thanks a lot!
I will keep you updated.
Omg thatās some big numbers writing, just disable baloo and kde search and its components in general in the kde control center, they seems to cause issues. That were my observations while trialing plasma desktop.