The Non-Effort of Isekai Anime - Why don't the try more and what are the Good Ones?

[MFauli]

I guess if you consider Rosaria + Vampire an isekai, yes, that exists. Manga only.

But "Cour 4" is like a handful of chapters.

Rosario is an episodic ecchi-comedy anime, not sure how after everything you got the impression that would be anything close to what I'm talking about.