The latest plymouth-git update has a bug. That’s why removing the splash kernel parameter disabled plymouth’s execution and allowed you to boot normally,
You can resolve this by going from plymouth-git to plymouth. The reason why garuda uses plymouth-git by default is because the “regular” plymouth package doesn’t receive updates as often.
To switch the packages:
sudo pacman -S plymouth
This will ask you to remove plymouth-git since it conflicts with plymouth enter Y to do so and continue installing. After the installation is done to update the initramfs follow the post below, It’s necessary for plymouth.