An Organization Wide call was introduced in 1-2021, but for the life of me I can't find it in the API V1 documentation.
It still works though:
https://api.meraki.com/api/v1/organizations/<orgId>/cellularGateway/uplink/statuses
Provides back all MG stats across the Org including 4G or 3G stats, SN, IPs, Provider, ICCID.
The APN portion has never worked - I have had an open request for 10+ months.
There is also a bug related to the connection type with the 1.11 code.