You can mess up android by installing third party apps, using shizuku, or rooting. If there is a distro as strict as vanilla android is for the average user, then you are right. I’m talking no root, no sudo, only official flatpak apps can be installed and only user’s home directory is r/w.
Even for an intermediate user, immutable might be a good choice, but it is extra unneeded complexity for a beginner, according to my experience with those type of distro in the past.
But people are different. Some might feel right at home.
Can you elaborate?