Any linux distro which has nice beautiful simplistic ui?

Trying to configure a smartphone which was already optimized for elderly users, with a more simplistic launcher, larger font size etc.

But the underlying Android 7 and its apps still keep showing up with their inconsistent UI and nagging messages and suggestions.

Is it even possible to configure any Android device to make it really simplistic and distraction free like, say, a classic NOKIA before the age of smartphones?

Culprit no. 1 Google and Android system. Suggestions about features keep recurring, even after stating that we are not interested in the feature.

Culprit no. 2 WhatsApp, unfortunately still the most popular messaging app in Germany, so this crappy bullshit software by Mark Fuckerberg's company has to be installed. Even to me as a tech savy developer, WhatsApp has a confusing user interface that tries to promote features like status (their versions of stories) without any option to hide / turn off.

How shall an 80 year old senior learn to use the app when they previously only used SMS and voice calls? I don't know.