Hello,
This is how I did it just recently. I have an centos 7 with a standalone ovirt engine and a couple off nodes with vm's running on them.
Make sure your environment is update to the latest 4.3 "engine-upgrade-check", "dnf update ovirt\*setup\" and then run "engine-setup" and also " yum update --nobest"
On the 4.3 engine you need to stop the engine "systemctl stop ovirt-engine" and even disable it "systemctl disable ovirt-engine"
Take the backup "engine-backup --scope-all --mode=backup --file=backup.bck --log=backup.log"
Then run "dnf module -y enable javapackages-tools pki-deps postgresql:12 mod_auth_openidc:2.3 nodejs:14" and "dnf distro-sync --nobest"
If you are using SSO on the oldenvironment you need to run this "dnf install ovirt-extenstion-aaa-ldap ovirt-engine-extention-aaa-misc"
Install the packages "dnf install -y ovirt-engine"
Then copy over the backup and restore them "engine-backup --mode=restore --file=backup.bck --provision-all-database"
Now run the command "engine-setup"
And that's it. make sure the ovirt-eninge on the new server is running "systemctl status ovirt-engine" and start it if it isn't "sysemctl enable --now ovirt-engine"
Now you should see everything again but still need to upgrate the nodes.
Kind regards.