My wife has a small business similar to yours, and I ended up building a micro CRM for her, complete with scraping (some of our vendors don't offer an Api), reports, invoicing etc.
so now we have good problems to solve like actually needing a CRM, invoicing etc that I hoping to do via a web app.
Once that is done, it could be sold to other similar businesses. I have already done some presales using my mockups and there is interest.
below you said you are running whatsapp sales for b&m shops, but how do customers find you? afaik whatsapp has no discovery features.
don't wanna post exactly how that is done publicly (yet)
I don't have serious hard numbers before that, as the CRM saw its first commit around sale #6.