Thank you for the detailed information.
If this issue started after the recent 25H2 security updates and it occurs on multiple devices
(with different hardware specifications, including Intel, AMD, and other chipsets),
then it does seem likely that the problem is related to the latest Windows updates.
Based on what you described, it also doesn’t appear to be caused by any third‑party software.
I hope Microsoft will release some information or a fix soon so that this issue can be resolved quickly.
Before the problem started, you probably installed one of the updates released this year,
from KB5074109 up to KB5077181.
Do you remember which specific update was installed right before the issue began?
If you can recall it, and if you have a device that is not critical for work or personal use,
you might be able to uninstall that update on just one of those PCs to test whether it makes any difference.