I may have a regression as well, but for me it isnt constant high stall, just I have noticed much bigger spikes that started on 24 Sept 2026.
I can see from shell logs, the dist-upgrade was done on 4:33pm Sept 24. Prior to this it was still Proxmox 9.x just an earlier build.
VM's using io_uring, I will switch to native, to see if is an improvement.