I've seen claims that the wifi 6E spec mandated that 6ghz networks required WPA3, so you would need to have a separate WPA2 ssid for legacy devices which therefore couldn't include 6ghz. A lot of access points now support a single SSID with all 3 bands using both WPA2 and WPA3, but I don't know if that is due to a change in the spec or if access points are violating the spec by offering that.
Can’t one SSID support different WPA versions across APs? I’m pretty sure all my devices just shrugged and connected when I downgraded my (single AP) SSID from WPA3/2 to 2 only and back up to 3/2.
Which is a bit sad, but also seems like it would allow this use case perfectly (assuming this was done on purpose and not just an oversight).