I fully agree with your distaste for big tech. That's why I'm here and not Reddit. However, if I launch an app on mainstream stores, I might get a couple hundred users relatively easily. If I push to the more niche stores/distribution methods, I might get a couple or maybe a dozen users. It's not that I don't want to distribute on the niche stores, but I need to prioritize what will get real users. But my goal is to find a distribution method that makes everyone happy. For example, I have plans to distribute the web version of my app via Docker, but I know I'll have a hard time getting people to pull a docker image. So I've deprioritized that for now. Same goes for PWA. I know I want to improve the PWA installation experience, but I know less people install a PWA on their home screen than app via App Store and Play Store.
That being said, the more people I have asking for a specific distribution method, the more likely I am to prioritize that. Unfortunately, every distribution method I add increase the friction for me to push new releases. I really want to be able to iterate quickly until Blorp matures, then as I find updates aren't as frequent I will build out to more distribution methods.
All of this could change, especially if I found more people willing to contribute to the source code.