You can easily test Apple Intelligence features in the EU on an iPad. You just have to set the system and Siri language to English (US) and sign in with a US Apple account under iCloud → Media & Purchases.
It even works with sandbox accounts! So if you don’t have a US account, you can easily create a sandbox one in App Store Connect.
Also note that Apple Intelligence is available on macOS in Europe without the need for a US Apple account. You just have to set the languages to English.
Topic:
Machine Learning & AI
SubTopic:
Apple Intelligence