Your salary doesn't have to be unquantified. Your own salary is an implicit cost that needs to be accounted for if you are viewing your efforts as an investment.
As an example, PayScale says average software developer salary is $67k in Springfield, MA. I would recommend you put this down as an expense and a liability or equity in the business within the context of the "accounting equation"; see https://www.investopedia.com/terms/a/accounting-equation.asp
The key here is to make explicit your opportunity cost. You can then put that in context of how much you are willing to invest in this business. For example, if you wanted to give yourself a seed investment of $300,000, this could mean $50,000 cash and 3.5 years of labour.
If you counted that as a liability you could say the business has to pay you back once it reaches profitability. Or if you view it as equity you would build that cost into when you sell your business. This would also allow you to better calculate ROI.
If you account for your time this way, you can cleanly separate business and personal expenses. In terms of the "4 hour workweek" way of thinking, it also means you know when you can stop implicitly throwing money at your business and hire someone to fill the "dev" role and have the business run itself.
If you will indulge my 2c, I would also recommend you cut any projects that are not performing to your expectations. When you have multiple projects you are acting as portfolio manager. This means that you are modelling your business like a much larger corporation with different business units, which require far greater management overhead.
From reading your post, I believe the role you envision for yourself right now is that of product owner/manager. If that's the case you should limit the scope and complexity of all other responsibilities so you can do that role well.