Hello, thank you for reaching out @pk !
I got into the US in August 2018 (on an F-1 visa) and stayed until September 2019. Then I came back to the US in August 2020 (on a J-1 visa) and have been on a J-1 visa until July 2022 (last year I filed my taxes as a resident for tax purposes). This year (in August) I started PhD program on an F-1 visa and according to my school I passed the "substantial presence test" so I am a resident alien.
I got two W-2s (one from my previous employer, until July 2022 + the other from the university where I am a PhD student); this is not my first employment. I got the 1042-S from the university where I am a PhD student. I am filing taxes as a single person and before my stay here on F-1/J-1 visas I visited the US several times on B-2 (4 times, up to 1.5 months).
I found the treaty between PL and US https://www.irs.gov/pub/irs-trty/poland.pdf (article 18) but I am not sure which part applies to me...
