Hi Kai and welcome!
In my opinion, there's really only one way to estimate the age of an unknown make of accordion and that is to gauge it by it's stylistic features (like you would with cars, clothes, aeroplanes, and buildings)
Looking at yours, I'd say it's pre-WWIl, from the 1930s.
As you say, given some TLC, there could be plenty of life left!
Some would say this type of thing would make an ideal project for an introduction to accordion repair!
Unfortunately, many people are unwilling to spend the time or money to do the necessary renovation.
It appears to be missing it's (rather attractive) fretwork metal treble grill.
However, a competent home handyman ( or someone with an old school panel beater friend) could probably shape a replacement from expanded metal sheeting.