I was able to do it just because I'm in software and I work with english speaking clients outside the EU and I'm just shopping for the best eu country that gives me the best weather / services / lifestyle with the lower taxes.
People outside of software have a hard time and are stuck in their country, exactly like they were before the EU.
Not really. It's very popular for Croats to move to Ireland to drive trucks for instance. There are businesses set up by Croatians in other EU countries that hire Croats who don't speak any other languages. People get the help of friends and family when they immigrate. It's been like that for many immigrants worldwide for a long time.
Hell, I couldn't live, work, state a business in most of the USA and we all speak the same language and share a lot of the same culture, currency, federal government. Etc.
Your combo sounds like Portugal. I agree there are probably differences between countries, but from what I've seen if your trade is in demand in the target country, it's relatively easy.
And it's even easier if there's an expat community you can reach out to for advice.