I'm having a real nightmare figuring this out, and I feel like it should be really simple.
I'm using a sharepoint list to track specific information from our users as they interact with various powerApps etc. I've previously been manually handling people's access to certain functions with an "AdminMode" variable and the OnStart property of an application in this manner:
If(
User().FullName="Simon Smith"||
User().FullName="First Last"||
User().FullName="First Last",
Set(AdminMode,true),
Set(AdminMode,false)
)
This is really inefficient, as it requires manual updating. I figured I could use my list that holds other info to also hold a department/role multichoice field, so this could be updated by others, rather than hard coded by myself.

My first attempt at applying this though and I've hit a brick wall. I'd like an element in Powerapps to only be visible if someone has the "Order Processing" choice selected in the "Department" field, but I can not for the life of me figure out how to do this.
Any pointers would be hugely appreciated, I assumed there'd be tons of resources relating to this, but I'm either using poor search terms, or it's so obvious that it's never needed to be asked before!