Contrary view. Your success running a lifestyle software business is likely to be far more dependent on your marketing skills and efforts that what what tech stack you use.
True, but here lies thus the paradoxical thing about tools: a good tools is one that stays out of your way when you want to do something, while a bad tools is one that requires you to focus on itself instead of the underlying objective.
Thus, a tool is the least important part of a project, while choosing the right tools might be one of the most important decision of a project.
The OP isn’t making a point about the software stack insomuch as they are making the point that your developer has you by the short hairs if the stack is too specific or if you have no idea how anything works. Use something that someone else will have a fighting chance to take over when the day comes that your developer gives you two weeks notice. And be sure to document everything.
I was being a bit contrarian. Obviously choice of tech stack is important. But, in my experience, people obsess too much over that and sepnd way too little time thinking about marketing. Also, choose reliable 'devil you know' tech over the latest flashy framework.
Thus, a tool is the least important part of a project, while choosing the right tools might be one of the most important decision of a project.