Similarly to you, I ran into this problem with virt-v2v 1.42 using OLVM 4.5.4-1.0.29.el8.
On submitting a request to Oracle via SR, they referred me to this: OLVM: How to Revert
from Keycloak to AAA (Doc ID 2999963.1)
So, there is a way to back out the KeyCloak oAuth 2.0 implementation and re-enable to
aaa/jdbc. I haven't attempted this yet, but I'm inclined to, because I already
having a working set of scripted tools that do a one-command-line migration successfully
under the prior OLVM releases.
If you're sufficiently dauntless, you could try a recompile of virt-v2v using a recent
change vetted by the Red Hat developers most closely associated with virt-v2v:
https://github.com/libguestfs/virt-v2v/pull/43 but this involves a number of dependent
libraries, and would not be supported until it is released into an authorized software
distribution.