For band steering to work, both frequencies need to have the same SSID. If the bands were split there would be complaints that devices weren't choosing the optimum band.
@licquoriceThat is correct but giving the option would do no harm. Likewise "Smart" gives many problems and is no longer as easy to turn off.
I have myself the synology rt6600ax, so far its been awesome, 900Mbs speeds on WiFi 6 devices....
Multiple 2.4 and 5ghz SSIDs.
@cooper-marshA great router but not so useful if you want to keep your landline number and have to change to BT's DV as it will only work with the Smarthub 2.