Hmmmmm. After reading what Darmur said above about the new version of Primo supports 5GHz, which also suggests that the older one doesn’t.
Ive just checked the specs for the Primo and it only supports WiFi 802.11 b/g/n
For 5Ghz you need 802.11 b/g/n/ac. ac meaning WiFi 5
So separating the SSID’s or even modding the config file wont have any effect if it cant connect to 5Ghz in the first place.