iPhone 12 and newer will default to a WPA3-personal security type using hotspot.  Because the R7 radio require WPA2, it may be necessary to enable the "maximize compatibility" option in the iPhone Personal Hotspot settings.

iPhone 12 and newer hotspot connection

iPhone 12 and newer has an option slider called "Maximize Compatibility."  Enabling this will force the hotspot connection to utilize a 2.4GHz wireless connection with WPA2 security type.

https://it-training.apple.com/tutorials/support/sup040#:~:text=Personal%20Hotspot%20uses%20a%205GHz,devices%20connected%20to%20the%20hotspot.