Ask HN: Strategy to raise money for smaller market size

We have a niche business for a particular industry but with very good domain expertise and traction. We have a few hundred enterprise customers and over 10 paying enterprise customers after just a few weeks since a first product was released. Investors are saying the market size is small. Total addressable market in the US is about 150M$ and around the world 800M$ per year (we are being realistic not exaggerating the size).

Any ideas how can we find investors that don't mind so much if the market size is smaller given that we have great traction, team and other factors which really lower the risk?

Thanks for any advice on this