I live in NL, and have a Vodafone SIM, I've been to Italy, Poland, Spain & Sweden since the regulations came into effect, and in all of them I had 4G or 4G+ on my phone, I didn't run a speedtest to check what I actually got, but I had no troubles whatsoever to use the internet the same way I do in NL.

Obviously 4G wasn't/isn't available *everywhere*, but I've seen no indication of any "throttling"