Have you tried publishing apps for the App/Play Store? Last time I made a game with Unity then I had to export it to different platforms and for some of them, such as iOS, then I had to make additional code modifications with xcode to get e.g. ads to work properly. I’d easily end up spending a day on making sure each store listing looked good (required files in different formats, and tons of settings to setup).

I also struggle to think of a scenario in which you wouldn’t want your app published on all app stores (unless you for moral reasons wouldn’t want your app on Chinese-owned stores or something like that).