SOLUTION: I found that the new iPhone13 will transmit a hotspot connection on 2.4Ghz or 5Ghz. In order to use it with the RRC-1258 MkII WiFi board, you must lock the iPhone13 at 2.4Ghz.
From Apple: Since some older devices can only use a 2.4GHz connection, like the RRC-1258 MkII, which can lead to compatibility issues, Apple has introduced a new "Maximize Compatibility" option so you can switch to 2.4Ghz when needed. When the Maximize Compatibility option is toggled ON, the hotspot will broadcast only on 2.4Ghz.
This setting is found under Settings/Personal Hotspot.
In addition, set the Control-RRC to DHCP using Microbit Manager. This setting is found on the SETUP tab, [Get From Device] button. This will allow the iPhone to assign an IP address to the RRC. I've setup a unique PROFILE to automatically switch from the default IP to the iPhone DHCP IP assignment when traveling.
