I have a Cayin N3 Pro and a Qudelix and in both the difference between the single and the balanced one is noticeable, if what you tell me is little difference in the Gryphon I think I'll have to return it since I don't see that of its more 1000 power
Perhaps you are looking at it the wrong way around, maybe the 3.5mm is performing better than you expect rather than the 4.4mm is performing worse than you expect.
I'd suggest that if both single ended and balanced outputs are working, even if not as you expect, then the unit has to be working properly. It would be seemingly impossible for them to be working improperly as the 3.5mm is literally fed by part of the same amplifiers feeding the 4.4mm balanced.
Does it sound good ? Does it do what you want it to do ? Does it perform well compared to your other gear disregarding a number on the screen ?
Perhaps stop worrying about what a number of the screen says and enjoy it - but that is over to you of course.