🚀 go-pugleaf

She was nominated for the Hans Christian Andersen Award in 2006.

Unfortunately, I can't find a real obit.

I THINK this is the same person, given that I found a couple of other tiny sources that say she died in 2021. Trouble is, I don't have an exact birth date to make a match.

https://www.wirtrauern.at/traueranzeige/heide-stoellinger
 (I don't know what the abbreviations "mag.art." stand for, but "geb." typically means "geboren" which means "born.")

https://www.bibliothekderprovinz.at/autor/heide-stollinger/
 (photo and two book covers) 

About the first book - Ein bisschen mehr Jubel und Trubel bitte  "A little more jubilation and hustle and bustle please"

"First tells the story, there is just a green square. I call it a meadow. This is very exciting. The people who look curiously into history from above and below, from the left and from the right, say: But that's not very much yet. A little more cheering and hustle and bustle please."

From Amazon.de (translation):

"Heide Stöllinger was born in Klagenfurt in 1941 and studied at the University of Applied Arts in Vienna. Many of her picture books have been honored with national and international prizes and awards, including the Austrian Illustration Prize, the Golden Apple of the Bratislava Biennale and the list of honors for the H. C. Andersen Prize. Her picture book "Esel" (Donkeys) was the most beautiful book in Austria and is an international long-running hit. She lives and works in Linz."

https://www.youtube.com/watch?v=glKsxo6r7FM
 (7:32 read-aloud of "Donkeys")

https://www.google.com/search?q=%22heide+St%C3%B6llinger%22&tbm=isch&ved=2ahUKEwiimZnVgbP6AhV8rIkEHaPZDCYQ2-cCegQIABAA&oq=%22heide+St%C3%B6llinger%22&gs_lcp=CgNpbWcQA1DNBlicGGCIGmgAcAB4AIABfIgByQKSAQMxLjKYAQCgAQGqAQtnd3Mtd2l6LWltZ8ABAQ&sclient=img&ei=ZuUxY6LOOvzYptQPo7OzsAI&bih=884&biw=1920
 (photos and book covers)

https://www.amazon.de/s?i=stripbooks&rh=p_27%3AHeide+St%C3%B6llinger&s=relevancerank&language=en&text=Heide+St%C3%B6llinger&ref=dp_byline_sr_book_2
 (more book covers and reviews - in German)