My Fabrik3 fileupload elements used to work with Imagick library but i had to change them all to GD to make them work in Fabrik4. I am not sure it is related to php version though. My Fabrik 3 site was running with php7.4 and Fabrik4 site with php 8.1.
I manage my server also so i install the necessary php imagick libs always myself and yes Imagick is listed as an option in fileupload. Joomla system error message (500 system error) is displayed only. no JS errors.
Deleting the line works. thank you. i had to delete the same thing somewhere else in the early days of fabrik4 while trying to make it work but i have forgotten that i did.