Law / How to get my passed mother's money from the bank? [4]

How to get my mother's money from the Bank which does not accept her WILL and document sign in Bank in case of her passing away?

Real Estate / Property Sale Tax [3]

I am a Polish citizen but have been living overseas permanently for a few decades.

I had my mother's apartment/flat gifted to me just prior to her passing away. I sold the property 5 years after the date it was gifted, but apparently it has to be 5 years after the new calendar year after the gift to be so there's no capital gains tax due, is this correct?

Let's say the property was sold for 500k. Does this mean I have to pay 19% capital gains tax based the value increase from zero to 500k, meaning I have to pay 95k in tax?