Been used in a few countries fine from what I know of and I live near Heathrow airport and use it to no ill effect. Though don't have the details of what bands they just opened up and how they compare with other countries and any impact.
[EDIT ADD] Whilst looking this document had a nice insight into the middle band usage globaly https://mma.prnewswire.com/media/1136543/5G_Mid_Band_Spectru...
Page 5 has current regions bandwidth assignment in that block and does seem that from that the USA is slow compared to other countries in assigning that band for consumer usage.
Page 6 has a nice visual showing the use/proposed use comparing regions - most insightful.