> it is impossible for a client to perform an atomic operation on multiple distinct objects types. > It doesn’t meet the “standard” for a rest api? Too bad. I

> it is impossible for a client to perform an atomic operation on multiple distinct objects types. > It doesn’t meet the “standard” for a rest api? Too bad. It is perfectly fine to model the creation of a product with options via a new resource. Another possibility is to model this as a transaction, a series of requests. Both meet the goals of atomicity and also following restful constraints. But since you disallowed those possibilities as the premise, there is no constructive way forward from there. Nice construction of a straw-man, must feel satisfying to see it topple over, but who do you hope to impress with that?