Have you considered bootstrapping until investors come looking for you? This question is a bit like how do we do marketing. The short answer is use your network

Have you considered bootstrapping until investors come looking for you? This question is a bit like how do we do marketing. The short answer is use your network to get intros. If that fails cold call (use LinkedIn, blogs etc for less generation). Make sure you target on investors that are interested in what you're working on already. You need alignment. Also consider that investors are like sheep running after trends. They also are only interested in companies that can reopen them 100x plus on their investment. You might have missed the investor boat for your specific type of company and that might be a blessing in disguise. If you bootstrap check out indiehackers.com . You can make a successful profitable business that you can work on full time without investors. In fact its easier now than ever.