Hello,
After installing Debian Buster, the luks-crypt font was too small.
It all went away when I installed Jörg Sommer scripts: I have a readable font now, in my case the one I'm using in the console: Lat15-Terminus20x10.psf.gz.
Just to add that I had to chmod 0755 both scripts - don't know if it was needed or not, but after regenerating the initrd (update-initramfs -c -v -k all) without the files being executable nothing happened.
Had to regenerate the initramfs with the scripts being executable.
Best regards,