Utterly failing to find relevant testers for my marketing tool MVP. Any advice/resources? [I will not promote]

I know this might seem like a sneaky attempt to promote my project, but I legitimately could use some input from people who have faced this type of connundrum before. My partner and I are building a marketing strategy and planning tool for small businesses. Admittedly we clearly did not do enough research or interviews with potential users before we just said, f'ck it and started building. Classic mistake, I know. We now have an initial MVP of the product that I think is pretty slick. But we've decided that before investing any more time into new features, we desperaetly need some real world feedback to help narrow down our ICP and guide our roadmap and post-launch marketing plan. For instance, we've been building with soloprenuers and SaaS founders in mind. But given some results I've seen so far, I'm starting to think this might be a better tool for indie e-commerce sellers (like Shopify or Etsy sellers) or maybe local brick and morters. One former teammate of mine even suggested making it more of highly customizable entriprise tool which would change the product plan significantly. So I guess in short, with the acknowledge that yes, this is all stuff we should have validated before building, how do you find early testers when you're still not totally sure about your ICP? How do you motivate people to try out a tool that you acknowledge is not quite ready for primetime? It's a real chicken and egg! Thanks in advance for any input, all!