When I hear the requirements in #3 I think of the Pacific Northwest. I don't know how far out from Seattle you'd need to go to find affordability #1. You can also look in Oregon.
The people in Portland and Seattle are actually very different. For the most part people in Seattle are assholes (check out the urban dictionary for the Seattle freeze) people in Portland are a bit nicer but it's a hard town if your focus is your career (maybe this changes a bit with remote opportunities - but I am still in the camp that remote devs are always going to play second fiddle to the devs at HQ/in-office if thats an option).
If you are going to move somewhere with a remote job, Seattle would be a terrible place. And to be honest the surrounding area is not a much better bet. With how bad traffic is, 90 minutes isn't going to get you to small cute cheap towns, in fact most of the towns just outside Seattle are more expensive. It's not an undiscovered gem.
As someone without a remote job currently in Seattle, I wish I could just trade spots with you. I don't even care how bad your situation could be. Feel free to reply if you want any questions about Portland or Seattle. Happy to help if I can.
Looking in Tacoma I'm seeing quite a few 1 bedroom apartments for <$1.5k a month which seems decent to me, and I imagine Tacoma is more expensive than some of the smaller surrounding towns. This doesn't line up with your comment so my question is, what am I missing?
There's really not much going on in Tacoma and taking the link from there to Seattle is a pain - sure its doable but you're talk about a huge hit to quality of your life. They are trying to make public transit better in the region but its a 20 year plan before its expanded to where it needs to be. The small towns around Tacoma are either military towns or also very expensive - Lakewood is basically a town for JBLM and Gig Harbor is mostly retirees cashing out and moving on the water.