Help Identifying An Austrian Or German Charity Stamp

Hi everyone,
I found a stamp in my collection and I'm trying to get more information about it. Here are some details I can provide:

-Text: "FÜR DIE HUNGERNDEN" (For the needy) "KINDER IM ADLER-GEBIRGE 5 HELLER" (Children in the Adler Mountains)
-Image: A girl working at a loom
-Value: 5 Heller
-Additional Text: There is a small inscription on the left side that looks like "C. Benesch Wien"

I've done some research and it seems like it might be a charity stamp issued to raise funds for needy children, probably in an area called Adlergebirge (Eagle Mountains). I think it might date back to the post-World War I period, considering the use of the Heller currency.
The mention of "C. Benesch Wien" suggests that it was designed by the Austrian artist and engraver C. Benesch.

I'm attaching a photo of the stamp for better identification.

Can anyone provide more details about this stamp? Specifically, I'm interested in the year of issue, historical context, and any other relevant information.
Thank you very much for your help!

For the starving children in the Adlergebirge.

It is what is called a "Spendemarke." This mountain range is on the border between what, now, is the Czech Republic and Poland. Considering the currency and the German language, the stamp will be Austrian. Austria lost this area after WWI. So, it must be pre 1918.

This source shows a brown one and claims it was issued during the period 1900-1918.

https://www.veikkos-archiv.com/inde...rge_W0438702

This site shows a range of colours
https://www.ca-collecting.com/shop/...n-25283.html

https://www.zvab.com/servlet/BookDe...rp0-_-title1

"Donation stamp, Austria, size 6x4 cm. Original old poster stamp that was used for advertising at the time. A catalog of seal stamps and advertising stamps is being compiled in veikkos-archiv. "

All the Austrian semi-postals in the Scott catalog say Osterreich, this was probably not state-issued.