The iPhone 12, which is the only one that supports 5G, doesn't yet support Virgin Mobile 5G
https://www.virginmedia.com/mobile
5G: 5G compatible device, Freestyle or SIM Only plan and coverage required.
Download times are based on average 5G download speeds Q3 2019 (at 140Mbps).
For more details see virginmedia.com/shop/broadband/speeds.html
Host a group video call in HD: HD compatible device required
Virgin Media 5G compatibility live date with iPhone 12 series to be confirmed
**********************************
I work for Virgin Media - but all opinions posted here are my own