Sounds like my situation. Started out with C++, then C# as a senior developer. Now on a Python job where I do not feel senior at all. On the contrary I frequently have to ask new hires that are straight out of univ about things. Nothing wrong with that per se, but it’s a bit too one-way now to make me feel comfortable or happy.
I also took some time off and developed a mobile app, but it does not generate enough revenue to live on. Is there some way for you to port your app to a different mobile platform and get it published? Surely you learnt a lot about making apps in the process, so it shouldn’t be a total waste anyway.
I’ve also thought a lot about leaving the field and keep programming as a hobby. Don’t know what else I would enjoy doing though. I realize work can’t be all joy all the time, but I think there must be some basic enjoyment. I see that my coworkers have that, but I don’t anymore.