I think this can vary a bit depending on whether youâre doing SRS elsewhere (I guess youâre also going through WK), how much time you have, etc.
My suggestion would be to avoid starting too many decks for now. Maybe just go with one. If youâre using Genki to study, you can take the opportunity to use the Genki Vocabulary Deck, or if youâre just looking to learn common vocabulary, you can study the Core 10000 words. Since you seem to be doing Wanikani, Core 10 has these tags L1, L2, L3, etc which represent the WK level at which youâll be able to read that word So that might be definitely useful.
Also, start with a lower amount of lessons. Maybe just go with 5 a day and see how you do. If you feel like later to can do more, youâll just need to adjust a bit I think itâs always better to aim for fewer lessons a day that you can actually do than overdoing, losing consistency, and feeling stressed about this whole thing.
Hope it helps!