I'm a US citizen and was working in Canada from April 2018 to April 2022 (work permit exp. April 30 2022). Do I qualify as a non-resident for 2022?

If you are unsure of your residency status, you will need to contact the Canada Revenue Agency (CRA) and confirm it with them. 

If you are in Canada or the United States, you can call the CRA at 1-800-959-8281. If you are elsewhere, you can call 613-940-8495. This page has more ways to contact the CRA: Contact the Canada Revenue Agency