Hello again, I wanted to share a further finding since the bug report was submitted.
Following repeated lock-ups making the system practically unusable, I have installed linux-image-5.8.0-2-amd64 (package version 5.8.10-1) from the Debian snapshot archive.
Having now tested this 5.8 kernel for several days without incident, it appears this is a regression in the 5.9 kernel.
Kind regards, Phil
