Brandes's piano pieces, likely from a later period, might explore more modern harmonic language and intricate textures.
Focus on precise voicing and control of complex tonal layers.
8 Klavierstücke (Op.22) is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7.
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.
8 Klavierstücke (Op.22) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.