I only got 3G or No Service at first on Virgin.
Here's what worked.
Go to Settings > SIM cards.
Switch it to CARD 1 under each entry of: Mobile data, Calls, and SMS messages.
Now 4G no problem!
Thanks, but all us Americans know you Europeans have the best phone service! Mine always improves when I go on an English or German network. Therefore, unfortunately, we can't compare access.