Sometimes I think I do worse when I try to digest chess lessons.
This is actually quite normal.
When we learn something new, our brains need some time to adapt to these new thought patterns. On a physical level, this means our brains are actually growing new physical connections, at a cellular level.
This takes time and energy ... so it's typical to notice you're decreasing in abilities, while this is happening.
Then, once your brain is done "rewiring" itself to the new knowledge, you might notice that your skill level suddenly "leaps" back up ...
I've noticed it many times over the years. Learning something new takes a toll ... but then once you've had enough of a recovery period, your mind will bounce back.
I find it difficult enough to get to 1000 in Rapid. Sometimes I think I do worse when I try to digest chess lessons. One recent opponent has been banned for fair play violations and I got some points back (yes, they're out there, folks!) though it is probably not the main reason. I started September tilting badly, have fought back but am now losing again. I am trying to limit my games per day as this slows tilt down even if it does not stop it.