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 spaced hiragana, spaced kanji and native kanji (without spaces). You need to edit the card templates for that, the basic approach is described here.
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.