Bluetooth and WiFi greyed out even the newest version

1) Try and Force Restart your iPhone EXACTLY as shown below and see whether that resolves the issue:

• Press and quickly release Volume UP button
• Press and quickly release Volume DOWN button
• Press and Hold the SIDE button until an Apple logo appears and then release the Side button (Can take up to 20 seconds. (DO NOT release Side Button when invited to Slide Power OFF). 

(2)  If that does not help, then this can be hardware related issue. Please contact 👉 Official Apple Support OR you can always get your iPhone examined at the Apple Store 👉 Genius Bar Reservation and Apple Support Options or at an Authorized Service Center for further diagnosis and evaluation.

Axel F.

If it’s greyed out it is most likely hardware issue with the built in antennas. Please Contact - Official Apple Support to set up hardware service

Try to open personal hotspot allow others to join,choose to use wifi and bluetooth.give time for the available devices to connect