The actual essay[0] is more tempered than the linked news release would suggest, and sounds like Professor Frank is hedging more than anything. The precise technology used is a complicated by 5G using different frequency bands between countries[1], even between providers [2]

[0]: https://jech.bmj.com/content/early/2021/01/04/jech-2019-2135... [1]: https://www.pcmag.com/news/upgrade-now-or-wait-canadas-5g-se... [2]: https://www.cnet.com/news/verizon-vs-at-t-vs-t-mobile-vs-spr... (Although this article is old enough things may have changed)