Everyone has their own process, but I think it’s fine to just start with a simple idea that’s not yet a game, jump in, and experiment around, especially if you’re just starting out. I’m not an expert by any means, but I managed to release a small game of my own recently, and all I had at the start was a test where I could knock over a box by throwing a ball. Everything else that eventually became the game were ideas that I had later while playing around and showing it to other people.

The only recommendation I can think of at the moment (at least that haven’t been mentioned yet) is Kaguya-sama: Love is War (admittedly I’ve only seen S1 since that was all they had on Hulu but it was one of my favorites)

Also maybe Ouran High School Host Club but it’s been a while since I’ve seen it so I don’t remember much