This work by the Latvian composer Alfrēds Kalniņš draws inspiration from folk traditions while utilizing the standard structural tropes of a Romantic ballade. It is notable for its expansive, sweeping gestures and developmental intensity.
The technical difficulty focuses on coordinating large, expansive chordal leaps with the prevailing cantabile lines.
Comparable difficulty and character — good candidates for what to learn next.
Ballade is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7. In the RCM system it corresponds to about level 7.
You should be comfortable at Henle level 5 — meaning you can already play level 4–5 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Ballade lasts about 6 minutes.
Ballade is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Barcarolle by Xaver Scharwenka, Blumenklage by Gustav Lange, Ballade No.2 by Nicolás Ruiz Espadero — see the full similar-pieces list on this page.