What is my best investment option as a Canadian citizen who is working temporarily in the US?

I am a Canadian citizen who just moved to the US and am making a relatively good money. My employer provides a 401k with a matching option. Most likely I will be working here temporarily for 3-5 years. I’ve been told that a backdoor Roth IRA is a good option to look at. What are some recommended tax/saving instruments or strategies someone in my position should consider?