The apartment is large (150m3) in a kamienica from about 1920.
My first was a bargain but managed to get it insured for current value at that time.
I don't know where abouts you are but, with kamienice, insurance companies are very strict when it comes to valuation.
Shop around for a better deal but you will find out that, with most insurers, there will be a difference in what you paid for
and their valuation. The key word here is "kamienice" and the history of such properties in Poland.
If it was a new built or something else, probably it would have panned out differently.