There have been plenty of fake movies within movies over the years, but only a few seem genuinely interesting enough to make fans wish they were real. Fake movies have historically been used in a variety of ways, although they’re often great for parody. Movies about Hollywood can have fake movies as jokes, and some movies take this idea one step further by making fun of themselves with a fictional stand-in.

https://screenrant.com/best-movies-within-a-movie-list/