However Red Hat now only supports conversions to OSV, since RHV was deprecated (sadly).
The biggest problem is oVirt itself has not proven to be a very sustainable open source project. If oVirt dies, we'll likely remove support in v2v. (There's a great start up opportunity here, for a dull but money-making company that productizes oVirt again.)
To move VMs from RHV to OSV you can just copy the disk image since they already should have virtio drivers, qemu guest agent, and be able to boot on any qemu/KVM-based platform. I believe there's some automation for that, but it doesn't involve virt-v2v.