The sugar, HFCS, and corn syrup are also only ingredients of the relish that is added to the sauce. The actual amount of those three ingredients in the sauce is likely very small.
Now I know how to cope with the Trump administration. Grow a beard, put on sunglasses, sit underneath a bridge and drink Big Mac sauce from the bottle.
You can probably go to a local McDonalds, talk to the manager, and see if would like to sell you a pack of their cheese. I'm serious about that. People don't know that you can get a lot of stuff you never thought possible just by asking.
When I used to work at McDonalds as a teenager we had people that would come and my manager would sell them our pancakes and other ingredients lose.