I don’t know what to do !!

I am not a beginner with dropshipping , I've been in the field for about 2 years, I've tried many online stores, some with a single product, some with several, but they were all bad and didn't last more than a week. Now that I've saved up some money, I want to get serious about opening a single store by the summer, but I can't decide whether to have just one product or several. Help me, and if you can suggest a supplier, I'd be very grateful 🙏