You can listen to FM radio on a phone without an active data connection, but only if your phone has an activated FM chip, and only with the right app.
Upgrade] Wireless Apple Carplay Single Din Car Stereo, Podofo 7 Inch Flip Out Touchscreen Car Radio with Wireless Android Auto, Bluetooth, Type-C/USB/TF/Aux, SWC, FM, Voice Control, Backup Camera - Yahoo Shopping
X-REAKO CarPlay Car Radio One Din 9Inch Car Multimedia Player FM AM Autoradio Stereo Android Auto 1Din For VW Toyota Nissan - AliExpress
Unlock the secret FM tuner in your Android phone - CNET
Enabling FM Radio on an iPhone
Simple Radio: Live AM FM Radio - Apps on Google Play
Listen to Radio on Phone For Free [Without Internet]
Applications Android de AppMind-Radio FM, Radio Online sur Google Play
Unlock the Hidden FM Tuner in Your Android Phone (CNET How To)
Single Din Touchscreen Car Stereo Wireless CarPlay Android Auto 2G+32G Detachable 10 Inch Touch screen Android Car Radio Bluetooth AM FM GPS Navigation WiFi Car Audio Receiver with Backup Camera 1
FM Radio Indonesia: Free Online FM Radio APK for Android - Download
How to play FM radio on a phone - Quora
Cafedelmar FM Radio