Do you run last qemu version? (8.1.5-2) (with the vm restart or live migrated to run the last version). Because they was a bug with iothread && this kind of lock when blockjob are running, fixed recently https://git.proxmox.com/?p=pve-qemu.git;a=commit;h=4ff04bdfa5f7f23cd2466789df1bf71559e84203