RBAC PHP by Bitwise Operators

I want to deploy rbac solution in my app. I found solution to use bitwise operators and it’s work but I have two problems.

1. In global meaning permission “write” is upper than “read” and obviously permission “write” sholud contain permission “read”?
2. For example I have page where I have form and inputs and I want to user access only read so I sholud use conditional “if else” ? If yes, that I have to two reapet the same code. One of conditional has to block form and inputs?

$read = 1;
$write = 2;
$deleteUsers = 4; 
    
$user = $read;

$employee = $read | $write;

$admin = $read | $write | $deleteUsers;


function checkPermission($person, $permission)
{       
    if($person & $permission) {
        return true;
    }
}
    
if(checkPermission($admin, $deleteUsers))
{
    echo "Access granted";
}