Double entry accounting system

So. I’ve now been here (almost) a month. With the help of old topics on this forum, a few videos and a Udemy tutorial or 2 I have built the app I set out to build, and a little bit more. Because it has been so easy I am now overreaching as I think I could probably add an accounting system into it as it would do everything I need.

My question is really, has anyone had any experience of this, maybe there is an app out there already which I could fork off? Would happily pay if I think it would do what I needed.