not true. I’ve written a couple personal apps that sync with health kit data collected from my Apple Watch and nutrition apps to help me track things in a way that is useful for my fitness goals. In 2016-2027 I used these apps to put on 30 lbs and stay relatively lean but I’ve never wanted to publish them in the app store. I don’t pay for any developer program. Just need to download some (free) developer tools / SDK for XCode, build the source, and put it on my phone. The install is tethered, but afterwards it stays there until I delete it. Restarting the phone doesn’t delete the app either. Only time I needed to re-install was when my 5s crapped out and I had to get a new phone.