I used Mitsubishis site to find the local “diamond” contractors (those factory trained and do enough volume). Then cross referenced vs yelp.

https://www.mitsubishicomfort.com/find-a-contractor

I see a few in Portland and several in nearby zip codes. Hopefully one can work for you. There are different tiers of “diamond” so you can compare if the difference matters to you.

One thing that’s a bit different is the air handler and outside compressor run on one circuit (mine is a 3 ton unit). So there’s a power line between the 2 units. That threw off our city inspector. But it works out nice since I now have an extra 20A breaker free :)