IKEA PAX wardrobe Vidal door does not close properly - tips?

Then it can only be the corpus. Either it was not assembled completely square or not aligned precisely. Even if everything was initially perfectly level, the cabinet could still have warped when it was attached to the wall and the screws were tightened after aligning.
The next step would therefore be to check the levels in all directions with a real spirit level. If everything is ok, you can only try gently pressing and pulling to see how it improves.
When adjusting the hinges, of course, you should not adjust only one hinge.

Thank you again for the help. Filling the cabinet has made the gap a bit narrower. I will leave it as it is for now and try again to see if I can manage the rest by adjusting the hinges.