You can do as much as you want and it is legal. But keep in mind that billing, pricing and currency will be also shifted to the country you chose + some apps might be also not available.
Like if you are in US, move your account to EU, then icloud/music will be billed in EUROs - euro payments might fail to your regular credit card - you will lose icloud/music. Also apps like chik fil a might be not supported so you would not be able install or update at some point - if you have it then you will keep using it until it asks to update - if you don't have it then you might be not able to fresh install.
Just for testing you don’t need to switch to EU, instead register a brand new Apple ID that’s in EU region.
Last time I check however, there’s a grace period for EU citizen leaving EU to continue to receive non-app-store app updates. And I don’t think you can enjoy sideloading by registering an EU account offshore.
Ask your local your competition regulator to investigate Apple for their anticompetitive policies regarding application software stores and encourage your local politicians to sponsor and adopt legislation that will enable more competition and freedom.
No. Big Brother is happy to make money from your European Apple ID.
But they're still keeping tabs on your location to force you into buying everything from them.
Following regulatory changes in countries such as the European Union (Digital Markets Act) and South Korea (Telecommunications Business Act), with additional enforcement...
theapplewiki.com
All the while advertising how they're protecting your privacy and touting their products' privacy features and restrictions.