Hi, Carullus, happy New Year.
I'm not that familiar with the German term, but all the English senses I'm aware of are indeed completely positive, not ambiguous.
Especially in contexts like programming or math, my impression is that it means a solution that can stand up against even a lot of challenges or heavy use, one that can deal with a lot of potential problems and still work very well.
I suppose a corollary or implication could be that it's not necessarily the most elegant or refined solution, but when you need a robust solution, surely that's not what you're looking for?
robust – ... 1b: having or showing vigor, strength, or firmness a robust debate
a robust faith
c: strongly formed or constructed : STURDYa robust plastic
d: capable of performing without failure under a wide range of conditions robust software
4: FULL-BODIEDrobust coffee
also : HEARTYa robust dinnerhttps://www.merriam-webster.com/dictionary/robust
robust – ... 2. Powerfully built; sturdy: a robust body.
3. Requiring or characterized by much strength or energy: a robust workout.
4. a. Active or dynamic: a robust debate; a robust economy.
b. Working in an effective way; effective or productive: a robust search engine; a robust hypothesis.
5. Marked by richness and fullness; full-bodied: a robust wine.
6. Substantial in amount: robust gains in stock prices.https://www.ahdictionary.com/word/search.html...