not in my experience, might cost more in the initial setup possibly (well within my plans limits anyways), then after that modifying and building the game is really incremental the AI game engine seems way more adaptable a fit for purpose. Costly thing with games (in terms of tokens) is generally dealing with images.
so not only is it a ton of code to write but it's a lot to debug and test. that said, it's a lot of fun writing your own engine from scratch if you are into that kind of fun. but if you want to make a game, why write the engine also?