I generally skip the PHP part. What I do is set up an acf-json file in the theme that I’m working on. When I’m done with a field group I move the json file for that field group to another folder and add a load point for that location. https://www.advancedcustomfields.com/resources/local-json/. I also usually have a site where I’m working on field groups and another site where those field groups are implemented. Whether or not I use PHP for a field group depends on if I need to make alterations to the fields, making the fields dynamic in some way, or if I need to be able to have the field labels and values be translatable. Might not be what you are looking for, but it is a different approach.
