@devansh-webkul I would be more than happy to contribute to the open source. But unfortunately there is not enough useful doc available to understand the whole flow. Probably this is the reason almost 90-95% folks contributing are from the core team. Rest 5% folks have mostly done a few bug fixes here and there.
Coming to integration with PG there are just 2-3 use cases. And all accept REST call to post a transaction (pre defined inputs) and it returns transaction status - success or failure. There cud be a few more secondary APIs. It cannot be more complicated than that.
If someone from Bagisto team can work with me then I can help make a generic module and make it available to all your users. I seem posts so many folks struggling with same few problem.