In the welcome line, use NAME= as the fallback for PRETTY_NAME=.
PRETTY_NAME= doesn't have to be set, but NAME= should.
Example output:
---
Welcome to Fedora Linux 37 (Rawhide Prerelease)!
[ !! ] This OS version (Fedora Linux 37 (Rawhide Prerelease)) is past its end-of-support date (1999-01-01)
Queued start job for default target graphical.target.
[ OK ] Created slice system-getty.slice.
---