What is the most useless app that you have seen being given as a subscription?
For me, I tried a 'minimalist' launcher app for Android that had a 7 day trial or something and they had a yearly subscription based model for it. I was aghast. I would literally expect the app to blow my mind and do everything one can assume to go that way. In a world, where Nova Launcher (Yes, I know it has been acquired by Branch folks but it still is a sturdy one) or Niagara exist plus many alternatives including minimalist ones on F Droid, the dev must be releasing revolutionary stuff to factor in a subscription service.
Second, is a controversial choice, since it's free tier is quite good and people like it so much. But, Pocketcasts. I checked it's yearly price the other day, and boy, in my country, I can subscribe to Google Play Pass, YouTube Premium and Spotify and still have money left before I hit the ceiling what Pocketcasts is asking for paid upgrade.
Also, what are your views on one time purchase vs subscriptions? Personally, I find it much easier to purchase, if it's good enough even if it was piratable, something if it is a one time purchase rather than repetitive.
If you're developing an app that has you provide your own backend then I don't think you'll be getting many average users.
You could also hide it in advanced settings to weed out those unwilling to learn and offer users a fee to use your server.
Ultimately the only reason I can think of not wanting people to self host is because you want to make money off having people's data.
The average user doesn't work like that, also an average user does not always think he is average. There are many people thinking they are advanced, because they know where settings in Windows or Android are located. You will probably get bad reviews then emails, because quote "your app doesn't work". This comment is based on real experiences with Google Play Store and its users, thinking they know what they do.
You clearly haven't dealt with the "average user". Get ready for a boatload of idiots who followed some crappy tutorial for "how to get it for free" making a problem for support or review bombing the app when they lose all their data through incompetence.