@MonkeyJo 

Indeed, if you assign distinct SSID, the roaming between SSID will not be transparent.

On the other side, if you specify the same SSID, but with different security settings to the two sets of bands (not specifying WPA3 for the 2.5/5ghz bands), the roaming might not work well for some devices.

(see the discussion here)

I suggest using the same SSID (& password) for the two sets of bands, and being prepared to fall back to two SSID if that does not work well.

  @yves_b 

Thanks!