Here is my product: https://matchkraft.com/. It is a marketing toolkit. I think you need to ask for feedback, asking why users don't want to pay for a premium subscription. So far, you are getting new users that is a good sign you are going to the right direction. Maybe, who is your ideal customer or maybe your product is ok but need more visibility (maybe paying ads). Try to get active users. I really want to... Source: 12 months ago

Calling a 3rd party API: There is a complete ecosystem providing "google-sheets-as-DB". I personally tested and recommend https://sheetson.com/ but there are a lot more with free tiers https://sheetsu.com/ https://sheety.co/. Source: about 2 years ago

The only competitor we can think of right now is https://startuptracker.io/ they combine information from leading providers with data crowdsourced directly from startups to make your startup research easier than ever. Data sources include: Fedger.io, Beta List, Crowdsourcing, Crunchbase, Product Hunt, Social Media. Source: almost 3 years ago