Are you failing the same things over and over again, or is it your long-term retention (failing all the master/enlightened ones you haven’t seen for a long time)? The attack plan is different depending on which you think.
If it’s mostly the new apprentice/guru ones you’re failing, then you’ve just hit a tough patch. Resetting to before it is one idea, or you could just put in some extra study. Say, pick 20 of those items, and study them so much you can never possibly miss them again. Repeat with another 20.
If you can get recent ones (current/previous level apprentice/guru) right, but you’re just not remembering when the master/enlightened ones come up, that’s a different and much tougher problem. Your memory decay is faster than the SRS “reminders” are designed for. You’re going to have to find a way to supplement the SRS, by reading, extra reviews (with the excellent Self Study Quiz script for example) or something. Maybe try also testing yourself in reverse meaning->kanji and/or learning to write the kanji with a pencil, involve all your senses and physical muscle memory. Unfortunately any change you make here, even if it works 100% for new items, isn’t going to take away the weeks and months of old items you’re weak on. A reset to a lower level is probably more necessary if you’re still getting buried by failed reviews in that case.