The way I see it, we’re all part of the same thing, which is the universe. And since we’re included, I see no issue in the personification of the universe.

I actually agree, but nonetheless personifying, and relating emotionally in this way to specifics, is useful because doing the work of actually relating all the cause and effect happening in between everything and a specific thing is generally an impossible task, so a shortcut to emotionally understand some specific as it's categories personification gets you a faster and maybe more detailed conclusion. It's in many ways just a mental shortcut enshrined in culture.

Same with a lot of the abrahamic stories if you read them as you would read Aesop's Fables there is actually a lot of good philosophical or otherwise human insight wrapped up in there.

In many ways it doesn't matter if there is flooding because we angered the sea, or there's flooding because there's a tropical storm and high tide, as long as we realize early enough that there exists a flood and we should seek high ground, warn our peers....

In this same way it mostly doesn't matter if everything is one and specifics are just phenomena of that one thing, like your universe, or what I'd probably just call nature, and others might call god, or if everything is a thing unto itself in constant relation to any other thing. If we draw the right conclusion.

So If you don't litter because the sign at the entrance of the trail told you so, or you believe it to be disrespectful to the mountain, or it is your duty towards nature to not pollute it, nobody cares and/or should care, but crucially any of those ways to think give you a good reason to do the better and harder thing, which is the reason all these ways of thinking exist.

A shortcut or a model of thought devoid of context is neither good nor bad, but in context I see the personified one true god causing much more harm recently. Not that the personified mountain can't be a harmful idea, it's just that in recent history it mostly hasn't been used that way.

If worshiping the Nekogami makes me happy and good to cats while not impeding me otherwise, why shouldn't I.

paganism works well with monotheism if you imagine that all could be a potential avatar of or personification of an overarching identity or deity which has multiple sub personalities due to omnipresence across multiple universes or timelines

It is real because we all believe it. The video game is a good example, we can shut it down and all your items are gone. Same with economy.