go to the Harvard MBA for Bootstrappers i.e https://longform.asmartbear.com

one of the recommended posts: https://longform.asmartbear.com/problem/ which goes to the heart of what you're experiencing.

play in large markets, very large in absolute numbers i.e B2B but small enough not to attract major VC companies - again play in large markets - don't listen to indie-hacker influencers that are making stuff for other indie hackers.

luckily everyone is running into A.I now - so there's plenty of things to be solved. not sexy, you've to look hard, screen hard (cz some opportunities look credible till you do the math i.e is there a large number of people, what is the willingness of those people to pay)

most of your work will be in marketing (marketing not selling) i.e researching to find out which problem will people actually pay for - what are the market dynamics - then only will you code a product.

tip: for a solo business - you've to be in an ecosystem kinda place.

I myself am facing marketing as the biggest challenge. I used to believe "a product so good that it sells itself" has to be the biggest lie. We're in this era where building and shipping are super fast, and reaching TAM has become the hardest problem.

just to add - you've to work the marketing problem from reverse.

how much money do you want to make - have an absolute cap on the annual amount e.g in 5 years you want to make 2m|5m|10m a year.

then choose your markets based on whether they can support that amount.