I assume you know that 2k means that it is base + catalyst. I am guessing that UP means ultraviolet protection, meaning it is ok to use as a topcoat. As an example the Southern Polyurethanes 2K epoxy is a great product, but they don't (or at least didn't used to) recommend it as a top coat or final finish, because of UV exposure.
You can still get Duponts stuff from a Axalta dealer. They still use same part numbers in most cases.Bring back the Dupont Dulux paint or even Centari. Today's auto paint materials are absurd.
What grit are you sanding with?I went ahead and just painted it...sanded it today...yup burned through some areas just like I thought I would....WTH! Now I have to sand these areas with a coarser grit just to lay more epoxy rather than the filler primer getting me closer to paint!