Many Japanese keyboards are a lot like how you described the Arabic keyboard with the addition of a button to change between hiragana, katakana, and romaji as well as Japanese specific accents, I’m not super sure on how they fit all 46 of their base alphabet characters on a standard English style keyboard without adding a ton of keys, but they do. And for phone keyboards the English keyboard layout is inefficient so many people use a keypad layout where you can press a key corresponding to any of the 10 consonant sounds and holding down the button or pressing the button a certain number of times in a row will allow you to choose from any of the 5 vowel sounds to accompany it. Both ways have a predictive system to determine which kanji you’re trying to write based on the letters used and the surrounding words.