Taxes, global warming, and population will all be issues that both the USA and EU will need to deal with.
So this goes to really the core of why I think the topic needs to be framed as what
cities to live in. While you may technically live in a country, you don't experience that entire country, you experience what goes on in your city. A great example is the USA and as morbid as it is to talk about, the homicide rate. Homicides are local - they can even be a matter of street by street within a neighborhood, but at the city level you see anywhere from a rate of around 100 per 100,000 in East St. Louis, about 30 in "normal" big US cities, 5 for the overall average, but generally only 1-2 per 100,000 in lower density suburban America.
Point is, it's important to pick a city that lines up with your expectations. I recall about a year ago talking about how much I enjoyed France on one of my Discord servers and many recoiled in horror basically because of all the yellow vest protests going on across France and how there had been a number of injuries and even deaths as a result. Bottom line however is that if you leave a particularly peaceful US town and move to a high crime city anywhere else, EU or otherwise, you're going to be disappointed.
While I'm not a dual citizen like some, thus I don't have the easy option of just moving to other countries than the USA, I'm not entirely opposed to reviewing options if there's a good reason to do so. Thing is - I already live in a town with a modest enough cost of living and exceptionally low crime / high stability. I bet the vast majority of people on here can say the same, well, I mean except you, haha. I can see why you'd want to leave Portland in particular. I have friends there that recently let me know that as soon as their son graduates high school, they're moving out of the city, possibly out of the whole state as they can't deal with the corruption and rioters that take over the protests any more, especially if they're only going to get worse every year.
Again - the importance of living in a city that works for you. For me, France is the place I could most easily see myself applying for a temporary resident visa once I'm FIRE though it probably wouldn't be in Paris, for example. Maybe Lyon, or perhaps a quiet outlying town of Bordeaux. I think there's great options all over the world, but especially in the US and EU. It's just harder than picking a country, since you have to pick a specific city that meets all the desired criteria.