So I just realized something. In UT, Omega/Photoshop Flowey feels less fun, easy, or enjoyable, because it’s supposed to be. He’s trying to make you feel like you’re in some kind of nightmare. A terrible one at that, where you die over and over and over.
Whereas in UTY, he is just trying to make you feel uneased, so his fight is more fun, easy, and enjoyable. This is also because he doesn’t have the human souls, and either only has yours or uses his own power of determination or something I forgot his fight.