Orbi 770 tri-band speed selection

There is no need to force the Orbi into 2.4G mode because it is already supporting 2.4G  Orbi WiFi provides a primary WiFi connection called a Service Set IDentifier (SSID) on both 2.4G and 5G frequencies.

https://en.wikipedia.org/wiki/Service_set_(802.11_network)   If the Arlo camera has only a 2.4G radio and can detect the Orbi WiFi, then it is detecting the 2.4G.  (With no 5G radio, it cannot detect the 5G signal.)

If the Arlo camera is not connecting, I suspect there is some other issue. (I sometimes regret making my WiFi password so complicated because I often have problems entering it on a tiny smartphone screen. Does the Arlo app allow you to display the password instead those horrid 'dots'?)