You may want to consider using CentOS 8 until Rocky Linux gets to 8.6. When RHEL 8.6 is
released, advanced-virtualization should become available to downstream distros, which
will make it viable to install oVirt on Rocky Linux etc. I personally had the best luck
with CentOS 8. CentOS 8 uses qemu 6.0, which isn't subject to the Q35 BIOS bug
you're encountering. 6.1 introduced the bug, 6.2 fixes it. 6.2 seems to be in release
candidate currently, so it's not available in repos yet. Most likely, this is why
CentOS (and RHEL) have stayed on 6.0.