I recently tried getting the latest FreeDOS running in qemu. I had a rough time getting it going, with the drives being rather unreliable, both C: and the cdrom. Even general reboot behaviour was not consistent.
I tracked it down to seabios, from this post: https://retrocomputing.stackexchange.com/questions/9367/qemu-emulating-ms-dos-cannot-access-cd-rom I built the Bullseye seabios package (1.14.0) on Buster, and the problems went away. Is this something worthwhile to upgrade on LTS? Thanks, - Chris