This is the holy grail for public domain music. While it hosts the original difficult versions, it also hosts "arrangements."
Here’s what I can do to help you find “easy Chopin” sheet music in PDF form: its easy to play chopin easy piano sheet musicpdf link
Look for "Chopin for Easy Piano" collections by arranger Jennifer Linn or Hans-Günter Heumann . They have published books that make the Fantasie-Impromptu feel playable. This is the holy grail for public domain music
In simplified Chopin, the thumb often plays the melody. The thumb is naturally loud. Consciously play your thumb softer than your index and pinky fingers. its easy to play chopin easy piano sheet musicpdf link
Which would you prefer?
Legality & Sources