Latest rpi-update kernel should fix the hang when vc4-fkms is enabled. Fix from here.
Not really sure what you are saying. That shows the kernel and modules are at 4.19.23.
First step build your own kernel: https://www.raspberrypi.org/documentati ... uilding.md
Is this a general problem with vlc on pi, or is this an issue purely in the new accelerated version included in raspbian?