First, to state the obvious: Hardware is hard. I have been doing hardware for forty years. I know. The cash requirements to build and sustain a hardware business can be brutally painful if you are bootstrapping.
One of the problems I see when reading about solo founders in the hardware domain is that they launch into the business without having 100% of the skills necessary to deliver the product.
When I built my first hardware startup I was able to complete all of the electrical engineering, firmware/software engineering, mechanical and had a pretty solid grounding in manufacturing. In looking at the profit statement for the OP's startup, I see $360K in costs that could have been avoided. That is, payroll, electrical engineering and web design. That's a ton of money.
My guess is the raw materials costs ($330K) likely is high as well. Hard to say without having greater visibility into the design. I'll say this, I would not be surprised if the cost could be cut in half by going to a reputable contract manufacturer in China. That's just reality, sorry.
The first quarter my product went on the market we (I) sold $650K of that product. The website didn't look particularly great, but it worked. I got better at web design over the years and improved it, eventually handing it off to someone else. At that point we were nicely profitable and I had several employees. The point is, if the product solves a problem the website almost doesn't matter. I always think of Craigs List as and example of that.
It looks like the OP devices sell for, rounding it, about $400. Which means 2022's sales amount to about 2,000 units. That's great, but the profits got eaten-up by having to pay people for skills. A device like this can be assembled and delivered 100% without having to hire a single person.
I recently had a case where I had to redesign a board three times due to component availability issues. It cost me nothing to do that work (in terms of cash), just a few nights and weekends of my time. That's the power of being able to do the work yourself.
My take is that solo founders, particularly if bootstrapped, must restrict their venture to whatever their competencies might be. If they don't, they will have to use cash to buy that expertise, which can make the difference between a nice grow path and extended pain and agony.
That said. Good job! Hardware startups can be horribly painful. I am currently helping a hardware startup that has to spend a million or two building prototypes before they can even hope to sell their product. Very different from being able to code-up a web product on a laptop in the dorm where pizza might be your greatest expense. It takes a special kind of personality to endure entrepreneurship in general, hardware entrepreneurs are on a different class altogether (which could mean we are amazing or we are absolutely demented...I think I am demented).