Visible will soon offer 5G service for phones in the iPhone 12 line. 5G service for some Android phones will be available a bit later.
5G won’t cost extra, but Visible suggested it may impose a speed cap (emphasis mine):
I’m not confident the 200Mbps cap will be enforced, at least initially. In the past, Visible mentioned a 5Mbps limit on hotspot speeds, but the company didn’t strictly enforce the limit.