I've got a BE200 WiFi 7 card installed in my laptop running KDE Neon 24.04. My network is WiFi 7 (Netgear Orbi 970s) with an aggregated SSID (2.4, 5 and 6Ghz).
My laptop won't connect to anything in the 6Ghz band, whereas every other WiFi 6e/7 device on the network can (2 Windows laptops, a Chromebook and mobile devices - Pixel 8, Galaxy S25 Ultra and Tab 10 Ultra), so I'm pretty sure the issue isn't the network.
My region is set to GB, I'm running the latest drivers (101.x) and the 6.19.x kernel via Mainline. The system doesn't seem to register 80211ax / be. On the rare occasions that it does connect to 6Ghz it's painfully laggy and slow even though the link speed is ~5Gbit.
5Ghz is solid (although fast.com tends to return speeds of around 500 - 600Mbit when the mobile device in the same room will return ~1.2Gbit. My internet is 1.6Gbit).
At this point I'm open to any suggestions.