I'm trying to be constructive with my thoughts, so my initial thoughts are: I've had a pretty different experience than you, and don't think your recommendations are good for a lot of people. IMHO you're taking too much risk doing what you think is a market need, when you should be offloading risk and making what the market is actively wanting/needing. This sentiment is repeated by quite a few commenters in different words.
Serial SMBer here, looking back at the dozen entities that worked in the past 20 years -- every one of my projects with 7+ figure outcomes had clear successes to validate the idea 3 months in, and I would often times MVP it off a contract with one client/vendor. (A few examples: niche used office furniture circa 2006, iOS app circa 2010, ML-based investing circa 2011, Amazon store in 2013 - so... all over the place.)
Just adding a bit of anec-data since we have quite a few people sharing what worked (and what didn't), the top 3 learnings for me have been:
1) Know people with deep pockets who want a problem solved - this means networking and establishing a niche for yourself as the go-to execution guy for problem X. I went to school near Sand Hill so that made it convenient. This simplifies your customer #1 problem as well as your revenue problem.
2) Know people who are good at solving problems, esp ones you dislike or can't solve. This is how you scale from a 1-person weekend project to a 1M+/yr rev project. You want this because a) problems that need multiple people to solve are a natural barrier to entry for anybody else, which means your solution is more defensible and b) partnerships are fun and when built right promote accountability where the sum of work is greater than its parts.
3) Entrepreneurship is hard work and should only be done as a last resort, if you know what you're getting yourself into, because you ABSOLUTELY WANT IT for whatever reason, whether because seeing something inefficient drives you nuts, that sorta thing. It's absolutely not for glory-chasers which I find kinda frustating, as a lot of (US) society glorifies it as such and sets peoples' expectations totally wrong and I see tons of miserable entrepreneurs burning out all the time in the startup orbit.