Regardless of the distribution, would it be possible to have a phone that can be simplified to include only the features you want? For example, I would only want a calendar, notes, a calculator, calls and messages. I wouldn’t want a browser, an app store or any other way to easily install them. Is this possible on a Linux mobile distro? Does it require a lot of work, like making a specific distro for it?
Linux feels like a great option for this because it can leave enough freedom to dumb down what you don’t need while also keeping a big level of customization, not everyone needs are the same regarding to dumbphones
The fact that you don’t want an easy way to install apps outside of the initial deployment but (presumably) want an easy way to update your pre-existing apps would probably give you some trouble because they usually come from the same source. There are ways to blocklist or whitelist packages on some package managers but the specific details depends on the package manager.
Remove the store app and replace it with a daemon which does the updates in background.
If it’s a pure Linux phone then apps would be installed through the command line and could be easily auto updated via a script.
So if you don’t install a terminal emulator on the phone itself and only access the command line through something like SSH. You wouldn’t have to worry about an app store at all ideally?