Ready operating systems for mobile?

Question

Operating Systems

There is an android tablet at home and I want to create "my own OS" on it, on which there will be only one application - mine. I imagine it like this: you turn on the tablet for the first time, there is a greeting, user settings, and then only my application works, that is, the logic that I set. I don’t need functionality like a regular tablet, I don’t need an application menu with swipes, settings, a camera, a gallery, and so on. In which direction to dig? It's like turning on the iPad for the first time, only after setting it up, my application will always be open, without other functions. Let it be a note-taking app (example). I turned on the tablet, wrote down a note and put it aside. You cannot close it. I found the Tizen OS, but I'm completely zero in this topic and have no idea how to remove everything from there at all, leaving only the set of functions I need. I only know Kotlin and C++, but if you need to - learn is not a problem. I'll be grateful for the tips.
PS: We need the ability to customize everything. Starting from the logo when turned on, and ending with the font in the application. Android Framework is not suitable.

Answer 1

Take a phone / tablet with Ubuntu Touch support and there you can easily make a kiosk mode. The rest you can easily cut out.
From Android, cutting out this whole thing is a thankless, long, and one damn thing will not work out that would be completely.

Answer 2

https://habr.com/ru/post/149561/
https://developer.android.com/work/dpc/dedicated-d...