Hello hello, welcome! Happy to hear you’re enjoying worshipping at the altar of the Crabigator learning kanji!
If you do 15 lessons a day, every day, you’ll end up with a review load of maybe 100-150 reviews a day when all the SRS stages are filled. Iirc, i did about 20-25 lessons a day and had seven day levels, and 175-200 reviews a day for a lot of WK. Assuming you review every day without fail or pause.
If you’re on PC, there is a user-script that looks at predicted daily review numbers. You can always keep an eye on that and lay off lessons if you’re getting antsy about it at any time.
Edit: And the WK dashboard gives you a weekly forecast of reviews, too, of course. If you feel like the numbers in the coming week are looking a bit high, you can also slow down or stop lessons for a bit.
Apprentice numbers cause the most reviews, since they’ll show up 4 times before going to Guru. So if things bloat, treading water until you get Apprentice and Guru numbers down some can create some breathing room. Always better to slow down than to burn out and stop!