I think it depends on your success rate on reviews now. If that’s super-low, like near zero, I would either reset or pre-study before attempting the reviews. If you’re pretty good on accuracy except for the apprentice/guru ones, then probably just doing 100-300 reviews a day is going to get you back in the saddle a lot faster. If you reset too low and that makes it too easy and boring, you won’t keep it up.
Also I wouldn’t attempt to get both SRS systems current at the same time or re-start kaniwani yet. I’d bring them back one-by-one, only trying to recover the next one when the previous one is back to reasonable workload.