Hey Greya.
You’ll have to find what works for you. My strategy before level 10 was clear reviews down to zero, then do all my lessors - as soon as they were there. After burning myself out (not entirely WK’s fault) then coming back four years later and taking 6 months to clear my huge review queue (level 10 for 1605 days 
), I created a few personal guidelines to keep it from ever happening again.
- No lessons ever if my review count is not 0.
- I do not have to do more than 25 reviews at a time (that being said, I usually drive it down to zero several times a day - use the phone app whenever you can steal a couple of minutes)
- No lessons if my “Next Day” is higher than 100.
- No lessons if my Guru count is higher than 500 (haven’t ever hit this, so I may decide to tweak it, if it ever occurs)
- I usually don’t do more than 10 lessons at a time or more than 25 lessons a day (sometimes not counting 熟語 that I can pick up instantly from knowing the individual kanji)
- Regular reminders that I’m here to learn kanji and vocabulary as well as I can, not to get to level 60 as fast as I can.
I also stay away from any scripts that change WK’s behavior, like the “oops” or reorder scripts. The only script I use is jitai, which is awesome. I’ve thought about similar kanji scripts, but, for me, it’s better to go look them up and compare side-by-side if I start confusing two (my current bugbears are 便and 使)
By my guidelines, from your screenshot, right now it’s OK to do 20 lessons. But, as I said above, this works for me, maybe not for you.
Good luck