Just throwing this into the ring...
try replacing $vt_handoff in the grub kernel line with vt.handoff=1 (from 18.04 to 20.04 it seems to have been changed from 1 to 7 to make the handoff to plymouth more fluid as it loads its own copy of the firmware splash to draw on).
Just throwing this into the ring...
try replacing $vt_handoff in the grub kernel line with vt.handoff=1 (from 18.04 to 20.04 it seems to have been changed from 1 to 7 to make the handoff to plymouth more fluid as it loads its own copy of the firmware splash to draw on).