I am trying to connect an iPad (iOS Beta 17.0 21A5268h) to our lab private 5G SA (Standalone) network. The network is in US and uses CBRS. Other (Android) phones and 5G devices are successfully connected to it. Per the article below, we have tried CBRS PLMN (315-010) and Test PLMN (999-99) without any success.
https://support.apple.com/en-ca/guide/deployment/depac6747317/web
Basic issues seems to be that the "5G Standalone" toggle on Cellular Data Options menu is greyed out with a message that says "Your current SIM does not support 5G Standalone. Contact your carrier for more information". Trying to choose our own network doesn't list our network (but lists other public 5G networks).
Same SIMs work on some Android phones and other 5G devices to connect to this network.
If you have successfully connected iPhone or iPad with 5G SA private network (not public carriers), some details/hints will be appreciated.