Ok - I took a view to the shop module - its core functions (not surprising as its obvious) are mostly the same to the one I have. I will keep it in mind while developing - you are right.
I definitely want to share the efforts. Unfortunately I cannot get fully involved from the next week, but I’ll do my best.
Then probably the easiest way is to deprecate your module and rename your database tables to match to the web_shop module tables. This will migrate the data from one module to the other. Then you can uninstall the old module.