You can see what values each API of Android OS returns.

Screenshot button
Easily save screen captures with a single tap.

Shortcut buttons
Directly open the network settings or SIM settings.

Supported APIs:

TelephonyManager
- getDataNetworkType (Android 7.0 or later)
- getDataState
- getLine1Number
- getNetworkType (Android 6.0 or earlier)
- getSimCarrierId (Android 9 or later)
- getSimCarrierIdName (Android 9 or later)
- getSimState
- isDataEnabled (Android 8.0 or later)

SubscriptionManager
- getDefaultDataSubscriptionId (Android 7.0 or later)
- getDefaultSmsSubscriptionId (Android 7.0 or later)
- getDefaultSubscriptionId (Android 7.0 or later)
- getDefaultVoiceSubscriptionId (Android 7.0 or later)
- getPhoneNumber (Android 13 or later)

SubscriptionInfo
- getCarrierId (Android 10 or later)
- getCarrierName
- getCountryIso
- getDisplayName
- getMcc (Android 9 or earlier)
- getMccString (Android 10 or later)
- getMnc (Android 9 or earlier)
- getMncString (Android 10 or later)
- getNumber
- getSubscriptionId

*Display based on information obtained from SubscriptionManager.getActiveSubscriptionInfoList.

Check out the code on GitHub.
https://github.com/tkm0e/telephony-checker