Now that we have agreement on check AC gauges, and put some kind of new oil filter on, with decent oil, and don't worry about a few microns because it is still smaller than what little hair is left in my head, and you will be changing every 5K, - your IR thermometer may be just the little helper you need.

Wait until truck is cold, pop hood, get ready to scan with IR, and crank it up. Focus around the exhaust manifold and where the flange joint transitions to the pipe leading down to the catalytic converter. IR will show like 400 degrees for hot exhaust leak.

I have the P1535 error but my AC is ice cold.

The AC relay is sparking. I bought a used relay. Still sparking. So I bought another relay. Still sparking.

Freon I understand. But it's ice cold. Maybe too cold. Exhaust leak? Oil filter? What do these have to do with the AC?