I was observing similar issues on four systems, two Odroid HC1 and two Odroid MC1, all running Armbian Odroid XU4 image. I think they were all upgraded from Bullseye to Bookworm at some point, but not recently. They run updates once per day, and it looks like the first failure was 2 days and 16 hours before time of writing. I observed "Hash Sum mismatch" errors and 404 errors, similar to OP, on each host, yesterday. Automatic updates started succeeding again about an hour ago.
My assessment is that one more more mirrors were probably broken for a few days, and just got fixed.
On the other hand, the openmediavault forum has thread 51654 on what looks like similar errors, and they seem to have recognized a problem with this upgrade path and applied a known fix to resolve. If you don't find that updates are suddenly working, now, I would check whether their solution applies to your situation.
