This is essentially the project I'll be doing over the holidays. I run a 3d virtual world start-up (today you'd call it a metaverse for sports - https://ayvri.c

This is essentially the project I'll be doing over the holidays. I run a 3d virtual world start-up (today you'd call it a metaverse for sports - https://ayvri.com https://ayvri.com). Most sports tracking apps view owning the user data as lock-in. I think that GPS/IGC/TCX/FIT data are a good target for decentralized and "personal" storage. For our app, we have tons of different user types, lots of pilots who want us to build a "flight log" for them, hikers and runners don't need any of this stuff, and there are already a bunch of flight logs that exist. So, my thinking is that I'll build what essentially to most people will look like an API to a users data. With the exception that I won't be running the only service that can access and use this API. It's open source, and available to anybody that wants to run it. Anybody who is storing their tracks using any app that uses that open and common API can use easily try out any other app. From the developer side, the technologies are still servers and databases. From the client side, I'll probably be hosting their "wallets" until they decide they want to take them somewhere else, or if I can figure out a nice UX a non-technical user can understand. So no, I don't think you are missing any key technical solution. Unless you are building your own blockchain, which I liken to building your own database because your app needs a database. That's my 2 cents at the moment, but I may change my mind in the coming weeks.