Yes, it's clear enough that they don't want you to be a member of that list. But what characterizes the elements of that list?! In any grammatical or intuitive reading of

"This probably isn't a good fit if your product is not backend-heavy, such as: ..."

the "..." is a list of things that are "not backend-heavy". And the first element is "iPhone game", which is certainly an example of something that is "not backend-heavy"!

> (Your product is (not (backend-heavy, such as: ...machine-learning models)))

Oh no! That's horribly confusing and not how lists are used in English! If that's what they meant, the post needs rewording. The correct way to say something like that is e.g., "Your product is back-end heavy but is not [insert delineating characteristics], such as: [insert original list here]".

To return the substance instead of grammar, IMO the "[insert delineating characteristics]" portion of that sentence is exactly what's missing from this advert!