selling one in Lublin you could maybe afford lock-up garage in Warszawa
Great answer! And something always to consider, especially if you're buying. Great to buy somewhere cheap; not that great when you come to sell again. And if renting, the difference in rental prices is usually smaller than the difference in sale prices.
Worth mentioning that Sh1tty is a juvenile across the Atlantic who couldn't find Lublin or Warsaw on a map.
One thing to add for the OP that's relevant to the thread. When people talk about districts in Warsaw, they often mean the boroughs (Żoliborz, Mokotów, Bielany, Białołęka, Bemowo, Wola, Praga Południe etc, etc). These are actually large areas, each with their own town hall and are administrative descriptions. Places like Stara Ochota, Stare Młociny, Saska Kępa, Kamionek, Powiśle etc) are neighbourhoods (often large ones) within those boroughs.
Warsaw is changing fast, and there's a lot of residential development. the metro (especially the northern part and line 2) are opening up a lot of new districts, plus there are some huge new flat developments, especially to the west of the city.
The district that someone chooses depends on a lot of things, transport infrastructure, the schools, the sort of shops there, whether or not people want to eat out locally, and of course the type of home they want to rent/buy.
The OP doesn't say if they're in Warsaw already, and if they're in a hurry to find somewhere or not. I'd recommend spending a bit of time looking at different bits of the city. What one person would like about, say, Powiśle, might be a negative factor for someone else. About Białołęka, a good (perhaps much better) alternative would be the eastern parts of Ursus (and beyond), or Łomianki. I like Targówek (Sh1tty would be doubtless fizzing with angst to see I'm recommending somewhere with a large PRL-era housing estate!) and that area has changed a lot due to development and an improvement in transport links; especially around Elsnerów, a bit of a no-go area 20 years ago, yet quite smart and safe now.
Warsaw doesn't define Poland
It doies however define this thread which is about Warsaw.