Get a tax advisor. The typical ending with a good one is
- SOC SEC / HEALT INSUR. in Poland
- INCOME TAX in Poland
- NO VAT at all (as long as you do not provide services in Poland)
If you want those to be in Poland.
There is a LOT of paperwork, even registering for an EU VAT number to go with the above.
Paying income tax in Denmark due to Denmark base is nonsense - for a contractor.