Mhm, I don't quite get why you want to postpone buying some of those components with your budget. I just slightly modified a build I did for someone else and it's based on German prices: PCPartPicker part list / Price breakdown by merchant

I think this hits all the requirements and it includes a 1440p gsync monitor (which might not be the best tho) and the best GPU you can buy, basically. The viability of the build depends on local availability and prices/or shipping cost to poland though. If you don't need Gsync, I'd instead go with something like the Dell U2515H (or the 27" version), cuz it's a very nice IPS panel (meaning great viewing angles). It'd be cheaper too!

Oh, the Evga PSU you chose is better, but availability in Germany seems to be limited. And i definitely wouldn't buy a 970 if you plan on going with a 980ti later on anyway. That'd be a massive waste of money.