The difference between the two is that Gnome is at least trying to constantly deliver stable and high quality desktop experience. I don’t like the way Gnome works, I don’t like the way their organization is run but I like when my computer just works. I don’t have time to fuck around with buggy Plasma widgets. I was a Plasma 5 users for two years until 2022 and I still use it on my Steam Deck occasionally. My opinion is based on experience.