My question would be, why are you calling update_post_meta() for every field on the acf_form(). because you are using an acf/save_post filter ACF has already save these values somewhere. If you are then saving the values somewhere else as well then you are doubling the amount of DB queries that need to be performed.
It really does not matter if you do this in one function or multiple functions, the result will be pretty much the same. It’s not the number of functions that need to be called, this will hardly effect performance unless you have thousands of filters.
Maybe you should explain why you’re doing all of these DB updates and maybe there is a better way.
