I think the caveat is that I misread your question originally, my apologies. I thought you meant coming as a tourist for a week or so. I’m glad you liked Warsaw but staying long term is a whole lot more nuanced. To be fair, staying for a long term as a black person, realistically, might be a bit iffy.

To answer your question, no, I’m not black. I have lived in Poland for a bit and know the language etc. Even as an ethnic Pole with an accent (I lived abroad mostly) I tend to get nasty looks sometimes despite being white. Ironically when my ex-gf lost her bag on a train they wouldn’t help us cause my Polish sounded non native, and they’d only help us when I put my father on the phone who is native.

To be fair this question would obviously require expertise from actual black people who have lived in Poland long time. Even in Warsaw or Krakow, you will most likely experience some negative experiences if you were to live there for a year or so. I wish you all the best and good luck though!