Great topic. We sound a lot alike. I work in a different sector, but I'm also now squarely in management and have been for a while, and my previous expertise was data engineering and infrastructure. Started with zero front end ability, and also not much Python either since I'm in the size of company and industry that still accomplishes most data work in SAS, and what it can't, Informatica and DataStage. Here's where I'm at, and so as to not bury the lede, I'm not making money yet but I found satisfaction in just spending some time each week on my projects -
1. If you know python, you can probably make a pretty natural jump to Flask. I didn't know Python, but I could program in a handful of other languages, so I figured I'd pick it up as a useful tool anyway. You may like this tutorial:
https://blog.miguelgrinberg.com/post/the-flask-mega-tutorial...
I'd say I really started learning when I got to the stage on authentication. The reason is that this tutorial implements OpenID, which isn't very common anymore, so I went off and implemented OAuth instead - heavily googling and scavenging, but ultimately having to piece together something that worked myself. I learned a lot that afternoon.
You could do this with any framework and there are tons of them. I chose Python and Flask over a Javascript-based framework because learning Python in parallel would be useful to me in data engineering, even though I don't write code for a living anymore.
2. As others have said, time commitment is the biggest issue. Figure out what you can give this, and scope appropriately.
3. I haven't done this because I'm too much of a completionist to pull the trigger, but get your MVP out there and build off of it. For me, I've decided I'm pretty happy just spending time on the project, even if no one else has seen it.
4. Bootstrap is my friend, it can be yours too. I have never been a strong visual person. I like words on a page. I have no eye for what makes a good visual and what doesn't, which has been my biggest developmental item when I moved into an executive role last year. All that said, Bootstrap is awesome and makes it a lot easier to build good looking websites. I started off here and built out a static website for an idea I'd had, and am now circling back to build the things I want to be dynamic in Flask.
5. There are a lot of choices out there. Unless you're developing bleeding edge, and I may get flamed for this, most of the choices really don't matter that much. I chose Python+Flask+Bootstrap because I liked each individually, it seemed like something I could work with, and NOT because I decided they were objectively better than Node, Angular, Express, React, or anything else that I haven't touched. I also sort of like that there isn't a new Python web framework each day, so diving into Flask seems like a more stable investment of my time. I'm sure there are drawbacks.
6. When it all starts to come together, the real, revenue generating idea might be to address pain points in your day job. My sector is insurance. I know a lot about certain operational functions. Eventually, I could solve some of those and build a business around it, I tell myself. You probably have some specialized domain knowledge as well. Consider that.
Good luck, and have fun. Like I said, I'm happier just for having taken on the challenge. If I ever make a dollar, that'd be good too, but less important than I initially thought.