How to Improve / Stop Backsliding?

I recently committed to doing a lot of puzzles because it is one of the things that was recommended for beginner / low ELO players. With that in mind, I decided my goal is to steadily increase my overall rating by the hundreds, and recently, I achieved my highest, a 2030 rating at puzzles. Unfortunately, it's been downhill since, and I've lost more than a hundred points. Actually, this has become a pattern: when I first broke 1900, I almost immediately dropped back to sub-1800 and had to climb back. Now it feels like I'm never going to get back to 2000, the puzzles have become too complex. How do I improve my puzzle solving abilities and get into the mid-2000s?

I'm asking how to improve my learning.