Louis Gobbaerts was a highly prolific transcriber and salon composer, and this work is a characteristic arrangement/fantasia on the iconic Strauss theme. It translates the orchestral splendor of the original waltz into effective, idiomatic pianistic figurations.
The performer must navigate wide-span left-hand jumps in the waltz accompaniment while maintaining a crisp, dance-like articulation.
Comparable difficulty and character — good candidates for what to learn next.
An der schönen blauen Donau (Op.86) is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7. In the RCM system it corresponds to about level 6.
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 An der schönen blauen Donau (Op.86) lasts about 5 minutes.
An der schönen blauen Donau (Op.86) 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 Bolero by Louis Gobbaerts, Blüthenduft by Louis Gobbaerts, Alla stella confidente by Louis Gobbaerts — see the full similar-pieces list on this page.