the formula of most story are like this : normal days of the protagonist, something changes it forever , hero save the world to come back to daily lifes again , plot twist :some good guys are actually the bad guys , bad guys motivation is nothing news , the monkey villain guy are take over higher dimensional , which is very cliche and feel no relateable to the reader , the brat demon 1000 years old guy is relateable but his asspull backstory out of nowhere is bad , I'm feel like most dead character in the series will be revive with plot armor because Apex magic and things , sorry it my english grammar is bad
That is not formula of "most story"; it is the formula for a narrative writing to be a story:
A character in their normal life, then there's an inciting incident that force them to go out of their comfort zone, and then a change occured to the character (whether it be good or bad change), then the story ends.
You can read Hero with a Thousand Faces by J. Campbell about the structure of storywriting.
Now, there are smaller parts in the The Hero is Dead that adds to this formula; the tropes used by the writer to tell the story. Things like funny perversion hehe actually matters in-universe, the sudden 180deg heel-turns of characters' allegiance (we have them multiple times here, both during serious moments and played for jokes), or conquering the
higher/other planes of existence (which I'm not a big fan of as they introduce massive chunk of info at once if not dripfed, though it gives the basis of the existence of Earth/Hell and magic in this manga).
Now, whether the author use these tropes well or not is up for debate, but personally, I hate it that it works here. The revelation of higher/other planes of existence would actually open up more venues for even more stories, but instead, it is used to end this manga. (I know the author had a sequel(?) in the works, but from my brief reading of few pages of ch. 1, it looks like it will focus on completely different character).