Just because someone says something on the internet doesn't mean it's true. It's critical to do the CBT or other work to remind ourselves of this.
There is no real get rich scheme. Someone might have 10-15 years of experience and know how something is priced in an inefficient market and know how to capitalize on it (they understand how people buy). In those cases there can be quicker approaches to leverage.
If you do not have funding, you probably need to set aside most startup advice. The resources and time you have available are entirely different.
Spending on ads can be a waste of time if you don't know know to retain the customers you keep.
Google one phrase: Founder-led sales.
Founder-led sales is what must be done before having delusions of product-l ed growth. I'm not saying it's not possible, it's just a question of whether you notice how many new things you're trying to learn to do at once.
The secret that you have available to you is you can spend one week building, and then one week in market showing what you've built and getting feedback.
Most people will make their life much harder by picking a startup in an industry that they don't know, trying to solve a problem they've never had nor know the depths of. It can be a subtle form of self-sabotage.
Being problem focused (problems of an identifiable company in the market that says yes to solving a probelm).
You must avoid the disease of building and selling an idea. Solving a problem that's verified is something else.
Back to founder led sales, this means, you, and you alone, must learn the needs from the market, and how to sell it, and get it going.
The first 100 customers is up to you. Do you know how to sell small, medium, or large customers?
Growth is about building an acquisition (marketing and sales system) that can distribute (product) something that can gain and retain customers from the market.