I have done both international EWR-Warsaw-Gdansk on Lot in 2022 (one ticket) and a hopper Krakow to Warsaw in June this year and it was just fine. I would say take the best fare and time combination. As others have said, it is always a bit of a risk to buy separate tickets unless you plan to spend a day or two in your first city. If you end up flying in to Gdansk, I called Uber, just because it was easy.
And just because thinking about it still makes me smile, here’s from my trip report of that arrival: “Upon arrival I called Uber from the Gdansk airport. In 4 minutes, Andrei, in his blue Skoda, was there. He hopped out, popped my small bag in the car, a touch sternly said “ Sit down” ( meaning “get in”), and we were on our way to the old town. We sat in silence for about 10 minutes, Andrei with his earbuds in, till I couldn’t stand it any longer and said “This is my first time to Poland.” Andrei pulled his earbuds out and had me repeat.
Then he said he had small English, to which I replied I had no Polish - which made him ask where I was from. I replied “The U.S.” and his face lit up. He said “I love USA!” And while we didn’t win awards for language skills, Andrei talked (and I listened lol) the rest of the way. He is from Belarus, made sure I knew the geography (Poland, Belarus, Russia), pronounced Lukashenko crazy, then pronounced Putin crazy, and told me a couple of things about Gdansk I didn’t quite understand. 🤣 (about Danzig, I think)
At this point, we arrived at my apartment and he made me wait till he opened the door for me, offered his hand to help me out, and then carefully handed my bag to me. We both smiled and went our ways: an ending not at all the same as the beginning.”