The jlab addon offers not only roumaji / latin characters, but also has kana/kanji trainers and furigana support. Using these tools, you can exactly determine, how many and which Japanese characters will appear on your cards. Without the addon, you can still choose between roumaji, spaced hiragana, spaced kanji with furigana and native kanji (without spaces). You need to edit the card templates for that, refer to the pictures below for details. The following fields are available:
Follow these steps on a jlab card:
On a jlab card, press “e” and follow these steps:
Another option here is to make adjustments to the writing systems using desktop anki with the addon and then syncing everything to your other devices, which don’t run the addon. This requires a change in [path to jlab’s data folder you set]/HiddenSettings.json. Set “fastCardUpdate” to false.