Calling WiFi 6 >1G is a pretty far stretch. I don't think I've seen a real world test that breaks that barrier in favorable conditions, even with today's routers:
https://evanmccann.net/blog/2022/5/u6-pro-and-u6-mesh-review
https://www.nytimes.com/wirecutter/reviews/best-wi-fi-router...
Whereas ultra-wideband was capable of pulling 2Gbps in 2020, something I have not even seen Wi-Fi 7 able to do. Ultra-wideband still has quite an edge:
https://www.reddit.com/r/ATT/comments/gbr335/this_might_be_a...
So yeah, when the author limits the tests to <1Gb none of the results were >1Gb. Who would have expected those results.
I've had >1G WiFi 5 networks in operation since 2018. It didn't require 6Ghz.
Your equipment or your environment may not have enabled it, but it was around.
> Until I installed 6GHz Wi-Fi
So after you upgraded your WLAN it was faster than your WAN until you bothered upgrading your WLAN.
That's a personal deployment decision not necessarily a matter of what was or wasn't' available at the time. >1G WiFi existed years before ultra-wideband was a thing.