Thank you very much for the detailed explanation. Your answers are really helpful for me to have something to start with.
To provide more detail for some of the ambiguity:
1.
I rented an apartment and went to an Oregon college in 2022 for 5.5 months before moving to Washington. I think I have abandoned my Oregon residency, but I'm not sure. I ended my rental lease in Oregon, rented an Airbnb for two months in WA, and filled up a new W-4 during my internship to declare myself a Washington resident (these were the all and only actions that I took) because I did not plan to return to Oregon ever, which still holds true.
2.
I have been holding a Washington state driver's license since 2019 and did not get any other because I hadn't been driving. Nonetheless, your description seems more appropriate because besides getting a WA driver's license, I did not take any action to establish residency in any state prior to 2022. I had my mailing addresses for banks and etc to be the places of my rental (2018-2019 Washington for 15 months, 2020 Oregon for 3 months), but all I was doing is going to school, so I'm not sure if that matters at all. Nobody can claim me as a dependent either because I'm in the US alone.
3. You are correct about the fact that I haven't taken any action to establish my WA residency. I signed a job offer with a Washington employer that will start in June 2023. All the other logistics such as W-4, insurance, etc haven't been brought to my attention by my employee.
4. I should probably stress that I did not earn any income in California.
I hope the 3 points above help clarify my situation a little bit. I think for now I'll try to go to the live tax advice and see what they think for a final confirmation, but I think it would be most appropriate to file as a part-year resident in all 3 states as you mention if I don't receive any further information.
Once again, your answer is really appreciated!
