Is it still possible to find enough developers for my team in Poland?

Yes. Poland has a pool of 250-300k software engineers which contributes to ~12% of all software engineers in Europe (2mln). Every year you can add 14k graduates, and 10k graduates from coding schools. Of course this is a very competitive market, where there is a shortage of programmers across the whole Europe. Success of building a team of highly qualified softwares engineers is a result of many factors like how interesting your product is, work culture and salary among other things.