Not just speculation but complete fiction. There are two respected historians who are 90% sure they have it right.

Key Research Findings
Identity & Origin: The girl is believed to be Rosa Müller, born on August 28, 1925, in Weißensulz (now Belá nad Radbuzou, Czech Republic), a location consistent with the filming area.
Circumstantial Evidence:
Post-war Activity: Records indicate she was held in US-run detention camps in Pilsen (Karlov 1) and later Ingolstadt, Germany.
Marriage: Documents show she married Hubert Wilhelm van Wyk on April 30, 1945, in Prague, and later married Friedrich Dürr in 1952.
Physical Features: Observers noted a ring mark on her left hand in the footage, which aligns with her marriage to van Wyk just days before being filmed.
Background: She was identified as a 19-year-old Luftschutz (civil air defence) helper.
Displacement: Research suggests she was beaten by Czech civilians near Ejpovice and was in mortal danger before being found. She later moved to Ingolstadt, Germany, in September 1945.
Current Status of the Investigation
Challenges: Some researchers have pointed out that "Rosa Müller" is a very common name, and concrete, irrefutable proof (like a direct statement or specific photo confirmation) is still lacking.
Obstacles: Recent attempts to access her birth records from the registry office in Belá nad Radbuzou have been blocked due to relatives forbidding the release of information, claiming harassment by researchers.
Validity: Despite the lack of a "smoking gun," the case for Rosa Müller remains the most credible and detailed theory currently investigated.
Researchers believe she survived the war, perhaps marrying again in 1952, and lived a long life, possibly passing away around 1995–1996 or even later, although some potential obituaries found for a "Rosa Müller" have not been definitively matched to her.

It's the best research so far, and is free of the fictional 'rescue fantasy' mentality of a lot of what we hear, especially some of the
you Tube video's.
Evidently some of the details of her abuse have been published online, and suffice it to say, after she had suffered the attack, somebody stamped on her face (sorry!) and it seems she has a broken jaw, who or whatever she is she did not deserve that. This is why she moves me and so many others to find out about her. As Eric Bogle wrote, it's happened again and again. Please excuse my bleeding heart but I'm not ashamed. In the video she shakes her head when asked a question, and then bows her head asking for mercy, holding a wedge of useless banknotes and her identity booklet. No wonder she is an icon of man's inhumanity, so maybe I am ashamed. Let's hope we have discovered her name at least.