Good question. If the 5GHz and 2.4GHz have the same SSID, the following solutions might work:
- https://unix.stackexchange.com/questions/419039/prefer-5ghz-to-2-4ghz-band-for-specific-wifi-network-ssid-without-using-bssid
- https://askubuntu.com/questions/1080645/how-do-i-set-5ghz-as-preferred-band
Both options require the use of the wpa.conf feature. That file can be edited from the dashboard configuration editor by activating the [x] Additional wpa_supplicant.conf settings option.