Don't let a feeling of a lack of expertise hold you back.
Early on in my adventures of trying to make some money off of products, I can't tell you how many ideas I had that I didn't pursue because of concern that I didn't know enough about the topic.
I'd ask myself "Why would anyone trust me on this topic?".
This applies to SaaS as well as informational products.
Fortunately I learned better over time. Otherwise, I could have easily applied this thinking (or excuse!) to this newsletter you're reading as well as the SaaS apps I've seen the most success with.
With the newsletter, I feel like there's a lot more I can learn about building businesses (is it even possible to know it all?), but I've started a lot of them and had a wide range of levels of success. While I feel out of my league with certain entrepreneurs, I still have something to offer them, and I often get asked for feedback and advice from people coming up behind me.
I've also had great success building lead generation tools. I would never call myself a lead gen expert, but because I've built products around this, some people view me as such.
There are a lot of people in the world, and your knowledge and expertise on any topic falls somewhere along a wide spectrum. Sorry to say, but it's highly unlikely any of us are the most knowledgeable on any given topic, or qualified in any field. But likewise, the opposite is true. We're each likely ahead of a subset of people.
Remember, in anything you're interested in sharing with the world, be it an info product or a SaaS app, aim for your best, not perfection. And know chances are incredibly high that it'll help a subset of people in the world if you know how to find them.
As always, you got this.