Hmmm, not what I was going for.
Every DM is going to have a different answer to "What if your players are having fun, but you're not?", so when I answered, I gave my personal opinion. That's all.
I remember finishing an 8 hour long 5e session and thinking to myself, "That was the worst game ever." Monsters were to easy, PCs figured out the NPC was plotting against them two sessions early, and the mage found a ring that trivialized my best trap. But then the next day, my phone was flooded with messages of how much fun everyone had. Oh, and their girlfriends heard about it too, and now they want to play. Also one of their little brothers is interested, what Starter Box should they buy...
Anyways, for me, that much happiness and excitement more than outweighs my thoughts on the game being "too easy". So as long as I can play PF2e, C&C, Hyperboria, or WWN regularly, I don't mind playing 5E on the side for those that want me too.