Comment by tranq_cassowary

If your criterium for choosing an OS is tinkering and hackability freedom to do modify almost anything to your liking (even if it will compeltely break your system or poke extra security holes in), then desktop Linux OSes ported to mobile might indeed be a good option.

If your goal is security and privacy (which go hand in hand), mobile OSes are clearly the best solution.

Anyway Android is still a Linux OS. The only requirement to be a Linux OS technically is to ship a Linux kernel. Adhering to freedesktop specifications like the FHS, using systemd, using GNU userspace software, etc. isn't necessary.

On Android you can install software by installing directly from APK files or you can use application stores which are package manager, they help you install software and if there are dependencies they can also install the dependencies if they support that.

Call recording is possible on multiple Android OSes, it's possible on stock PixelOS and GrapheneOS, I'm not sure about others but normally it's just part of the Dialer app. You don't need root at all for that.