Are some plot/story ideas (or certain combinations) inherently incompatible?

I’ve essentially given up writing because the one story I was interested in writing seems incredibly flawed from the premise. After struggling with it for years and writing 150k words of largely disparate scenes and “moments” from throughout the book with about 100k words of “connective tissue” missing that I couldn’t come up with, I eventually gave up.

That got me wondering if some (for lack of a better term) ideas or premises fundamentally don’t work and aren’t worth even trying to salvage.

For example, basic premise was like if the Stand By Me boys go on a Pokemon-like journey to Mordor to meet the Valyrian gods, but High Priest Sauron is planning a government takeover so that when main Stand By Me boy (lost Targaryen prince) meets and is anointed by the gods, the throne will be ready for him and the Targaryen reign can return as a theocracy.

But it’s a Joker-like character study of the Stand By Me Boys (and main boy’s father Ned Stark who’s trying to stop Sauron from getting to his (adopted) son) that’s focused on the characters’ relationships (especially father-son). The story isn’t about the journey to Mordor and the characters’ succeeding in defeating Sauron and his plans for domination. It’s about how the character dynamics change throughout the long and perilous journey where best friends become enemies and enemies best friends and how small white lies meant to protect the other have unintentional consequences. The drama and emotion, “the point”, come from experiencing how these characters interact with each other, the good and the bad and the happy and the sad, with the struggle of the journey further exacerbating cracks in some relationships while mending others.

In my case specifically, it seems like it’s an incompatible story and goal, so that’s one of many reasons why I’ve completely abandoned it.

This got me wondering if some things that, by their nature, cannot work together. Perhaps Idea A + Idea B alone aren’t incompatible (eg Pokemon + Ancient Rome), but something like Idea C + Goal D (eg War and Peace-like epic + set entirely in a kitchen).

Just to be clear, even if my specific situation isn’t inherently flawed or incompatible, I fully understand I’m not the person to write this story. I’m just asking about in general if some things cannot work regardless of how skilled the writer is.

Thank you.