Polish citizen moving tax residency from Portugal to Poland: advice?

Hi all. I am a Polish citizen with a Polish passport, but I have never lived in Poland. My wife and our two young children are Polish too. We live in Portugal now and I am tax resident there. I run a technology business that earns mostly from clients in the United States.

We are thinking about moving to Poland in 2026 or 2027 and making Poland my tax residence. I would love to hear from people who made a similar move in the last year or two, especially if you are self-employed or have foreign clients.

- What steps did you take, and in what order? Address registration, tax office, opening a business, health insurance.

- How long did the whole process take?

- Did you use the return relief (ulga na powrót)? Did the tax office ask for proof later, and what documents did they accept?

- How did you choose the move date, especially if your family moved at a different time?

- Which tax setup did you pick for foreign clients? Any regrets?

- What did advisers and accountants cost you? Any you would recommend?

- What surprised you most?

Thanks in advance for any real experiences.