Forgive me if this is yesterday’s news to some of you, but I just found this amazing replacement for the proprietary Japanese keyboard simeji: sumire
That’s all.
Also, if anybody here happens to already use it and know whether it’s possible to adjust this somewhat ugly disproportionate toolbar, please advise!
Not sure about the toolbar issue, but you can also use Fcitx5 (available on F-Droid). It doesn’t support the 12-key keyboard you’re using though.
Precisely the reason why I’m not using Fcitx, on a touchscreen there is nothing better than flick input for Japanese.