I'm looking to invest about 50,000 ZL
That's far too little experience, and far to little capital to even start thinking about starting your won business in Poland.
a business that can do Web design/development, IT project management, Mobile apps design/development, social media marketing, outsourcing
There are scads of businesses doing that in Poland already, all with significantly more experience and capital than you have at your disposal. Breaking into this sector would be impossible for you.
Also, without advanced knowledge of Polish, you would be severely crippled compared to the competition.
Starting your business in your homeland makes infinitely more sense. If you can't do it there, then you certainly won't be able to do it in Poland.