[operatorequals]

There is a Greek movie based on the exact same idea. Its the "Alps" by George Lanthimos (later known from "Dogtooth" movie).

I don't about Japan, but that movie had a quite depressing ending (not to mention that the whole thing was kinda creepy and unsettling).

[kazinator]

There is also, unsurprisingly, a Japanese movie based on that exact same idea. More than one, in fact.

It plays a part in Noriko's Dinner Table.

https://en.wikipedia.org/wiki/Noriko%27s_Dinner_Table

This is referenced in the plot summary: [...] As it turns out, however, Kumiko has no real family, and the people she introduced Noriko to are paid actors working for Kumiko's organisation, I.C. Corp. The organisation offers paid roleplay services to interested clients, allowing them to fulfill their fantasies of a happy family life.