There is a theory called diffusion of innovation. The simple explanation is that there are 5 different cohorts of buyers. Early adopters, visionaries, pragmatists, conservatives and laggards. Early adopters and visionaries are risk takers, who will make bold moves to achieve order of magnitude results. This is called the early market, which represents 13% of the market. The pragmatists and conservatives make up the mainstream market which is about 70%.
In order to get into the mainstream market, you need solid adoption from the early market.
To choose a niche, you need to develop a solution that fits nicely into the buyers expectations for different types of market participants. There is the market alternative and product alternative. The market alternative is the solution that owns the highest proportion of market share. The product alternative is innovative tech that challenges superiority to the market alternative.
You need to introduce a solution that fits in between those participants to stand out.
To choose a solution, go to industry trade events and talk to people about high value problems that aren’t solved by current participants. That is the purpose of industry associations, to solve difficult problems.
Visionaries and early adopters love new vendors. They will champion you through their organization if your solution will help them meet their goals.
Good luck