Deities in fiction suck, no?

So I've been finishing volume 11 last week and thought about something that annoys me about most fantasy novels, anime, manga etc.:

Why do writers always have to introduce their "own" pantheon of deities?

It's such a cheap plot device. Basically whenever you've written yourself into a corner story-wise or you need to raise the stakes somehow, the most brain-dead solution is to introduce a bunch of gods that fit your narrative. I had to take a break from the novel back when Windsom saved Arthur from the prison in the flying castle and now all this recent fate stuff is even more ridiculous. So you're saying that "Fate" is something conscious that led Arthur to where he is now? Ok, so "Fate" is TurtleMe basically, no?

When I wanted to write this post last week I already thought of a joke about how the real OG writers use multiple layers of gods:
"The current ones have become too weak? Well Uhm actually, these aren't the real, definitive gods. The gods of the multi-dimension continuum are even stronger!!! 🤓"
And BANG, with this weeks chapter we find out about the "devas" xD At some point the stakes become so high you just cannot relate to it whatsoever. We're fighting deities, so what's like at stake, planetary destruction? Again!? Uff.

And literally everybody does it too. Just at the top of my head: Solo Leveling (extra points for Ragnarok for multiple layers of gods), Naruto, Fullmetal Alchemist und a bunch of others.

Why does no one try to replicate something like LotR where the majority of players are introduced at the beginning and you create an interesting, grounded story? Lots of room for character development, relationships etc.