I forgot to ask but from this other thread you mentioned that you're on Zorin OS 17, while I've been testing on Z18... Well, now I'm not so sure I want to share this workaround as I'd like to test it out first. If you can give me a couple of days to be sure, maybe I can find another solution otherwise I'll post my hacky around it.
After trying out for a while I've failed to get this to work as intended, and now even on Zorin OS 18 there are issues with my approach so I won't paste it here to avoid any confusion. It seems to me that polkit is just really buggy.