I’d just power through your reviews. When you come across a kanji you don’t remember, also take a look at what vocab it appears in. If you’re really not getting anything right you might wanna reset a few levels, but 20 levels takes a long, long time and if you’ve already stagnated once (and had to reset all the way) it makes it really easy to just give up after 6 or 7 levels. Accuracy doesn’t need to be perfect, anything you get wrong you’ll review again soon anyway. You can also pick up a self-study script, it’ll give you random reviews of whichever set you want (kanji only, a certain SRS level, everything, whatever) to give you a refresh without it affecting your actual accuracy.
And echoing what everyone else here has said, don’t do any lessons. How big is your stack? I’ve found that sitting down with some decent music, a cup of coffee, and absolutely nothing else to do that night can do wonders on your pile. After losing internet for a few days I had a pile of 900 reviews, and I did them all last night. Sucked, but you’d be shocked what you can do in one sitting.