Talk to friends and family, see if you can build something to solve their problems that doesn’t exist yet (or cost too much or does a poor job). The more removed they are from the tech sector the better.
OR - do general client work (cold call or go door-to-door) and try to find gaps that way. Maybe you corner the market on sub-industrial sprinkler repair management software.
Our industry is hostile to vibecoded tools while the rest of the world waits for us to replace their legacy garbage with something better, vibecoded or not.