Better presentation of longer sentences is needed for language learning. Focusing on small bites of vocabulary can easily become counterproductive to fluency.
As for Japanese if you can find a way to separate individuals words/parts of words for ordering into sentences then this would be far better than typing out entire sentences or tapping on letter boxes.
When learning a language it is far quicker to translate a sentence verbally. Typing it out letter by letter is necessary only for tests and for spelling checks. If fluency is your aim then ordering the words should be enough for the purpose of “testing”
On the ANKI program we can see many users who have uploaded sentences with only their translations. Users check themselves whether they know or not.
Glossika spits out audio sentences for you so you can enjoy the learning process and don’t need to fiddle with a screen. Again you choose whether you know the phrase or not.
Some kind of mode like this could be helpful.