i can confirm that in (the german-speaking parts of) switzerland “handy” is the only word i’ve ever heard used to describe a smartphone

idk what circles you guys live in but I grew up in rural south and been living a decade in Berlin. If a German talks to a German and they are not doing nerd talk and are just commoners having a chat they have been and still are using the word “handy”. It still is the most commonly used word to describe a mobile phone in German language

In my friend circle, it’s usually just “phone”.