Sorry, I don’t have other suggestions at the moment.
Maybe let’s try removing Plymouth from dracut, but it’s really a shot in the dark.
Create a configuration file like this:
sudo micro /etc/dracut.conf.d/omit-plymouth.conf
Put into that file:
omit_dracutmodules+=" plymouth "
(the spaces before and after are important).
Save and exit, then:
sudo dracut-rebuild