I would try to upload an excel file with two Column The first put "Full Name" and have the second name it something like "Privilege"
I.E Below for now we will call this table reference.
| Full Name | Privilege |
| John Doe | Owner |
| Jane Doe | User |
| | |
Whatever fields you need hidden you can set the visible property to something like this.
If(IsBlank(Lookup(Reference,Filename=User.()FullName,Privilege),If(Privilege="Owner",true,false),false)
The idea is that the code checks the current username of whoever is signed in and matches it with the table and then checks to see if they are an owner or not.
The good thing about an excel spreadsheet is its static and can be uploaded right to the app so it does not need to take time to check a Sharepoint list.
Let me know if this is along the lines of what your looking for and if you need help with the formula let me know.