I reset from 21 to 10 when I came back, it didn’t help as much as I’d have liked. A large number of radicals had been renamed since I started and none of the mnemonics stuck anymore. I ended up resetting to 3. Made it back to 10 and burned out again. I reset to 10 again recently and have been back for a while now. Pretty consistent now at 8-10 days a level. Yes there are a lot I did the first time through, but honestly I don’t remember that many.
Of course there is now a setting to use the old mnemonics.
It’s not a race, reset to the level you’re comfortable with, maybe go down by a few at a time.
Lastly whenever I have more than 150ish reviews I use a script to do back to back reading/meaning. I find it lets me get through them significantly faster at the expense of trouble remembering some of the more difficult ones.