I'm lazy so I just fire off the occasional speed tests using Ookla.
It doesn't _really_ seem to matter what channel width or frequency I use, I tend to get around 600Gbps from my iPhone (17, pro).
When you make it a point to ensure you're on the correct AP, line of sight from a few feet away, sometimes I break 1Gbps. I was surprised, watching TV the other day, to randomly get a 1.2Gbps speedtest which is one of the faster ones I've seen on WiFi.
(10gbps internet, UDM Pro, UDM enterprise 2.5Gbps switch for clients, PoE WiFi 7 APs on 6ghz).
Honestly, I'd say overall 6ghz has been more trouble than it's worth. Flipping the switch to WPA2/3 as required by 6ghz broke _all_ of my clients last year, so I had to revert and now I just have a separate SSID for clients I have the energy to manually retype the password into. 6Ghz pretty much only works line of sight and from a handful of feet away. There were bugs last year in Apple's "Disable 6e" setting so it kept re-enabling itself. MLO was bad, so it would stick to 6ghz even when there was basically no usable signal.
Over the course of the past year, it's gotten pretty tolerable, but sometimes I still wonder why I bother-- I'm pretty sure my real world performance would be better if I just turned 6ghz off again.