Show Plymouth boot screen error

Can you please boot into Recovery Menu:

Once you arrow key down to Drop to Prompt,
run

mount -o remount,rw /

sudo update-alternatives --config default.plymouth

Choose the Zorin Logo option from the list by typing the corresponding number. It may be 0 or 1...
Once you have done the above, be sure to update initramfs:

sudo update-initramfs -c -k $(uname -r)

After all the above is completed, back out of the recovery menu and test a normal boot.