Comment from the launchpad counterpart to this bug below:
https://bugs.launchpad.net/ubuntu/+source/vlc/+bug/1991418/comments/10
"So, hate to rain on your parade, but as I wrote yesterday, the problem
doesn't occur with upstream (building manually) 3.0.17.4. So there are
ostensibly no patches to backport from upstream 3.0.18-rc2. This is
probably an issue in the Debian packaging or at least that is triggered
by Debian packaging.
Since it seems to affect only the Qt UI, it is most probably a problem
with the last Qt update. Again, please check with --no-embedded-video."
