For either long-term renting or Wohnen auf Zeit (shorter term, furnished rentals) in Germany, is a Haftpflichtversicherung (liability insurance) normally required? For example, I looked through the Youniq furnished apartments for a Zweitwohnung (secondary residence), which are mostly but not only rented out to students, and they require not only what I would expect (Arbeitsvertrag (work contract), Einkommensbescheide der letzten drei Monate (evidence of income last three months), Ausweiskopie (copy of ID)), but also a Bestätigung über Haftpflichtversicherung (confirmation of liability insurance). Although not a problem per se to obtain, it does add yet another layer of complication of newly settling in Germany, which may be hard enough as it is. Is this a usual requirement, or is this something particular?
I now have an additional datapoint from my son who rents a flat in Germany. His landlord did not demand to see the confirmation, but they did "require" that he had the insurance.
I think we can therefore conclude that this is not an unusual requirement.
Haftpflichtversicherung is quite cheap, so I would just buy it. You probably can't just fill in a form on a website (which is going to be set up for the "normal" case), but I suspect a phone call to an insurance broker will be successful. You might have to give a correspondence address in Germany, but you can probably use your new employer for that.