Hello KGBeatz,
Thank you for using Apple Support Communities and for sharing these details with us. We’d like to recommend some steps to see if we can get this issue with this specific setting being greyed out. Please follow the steps below to further isolate this issue:
1.) Restart your iPhone to help refresh things.
2.) Check for any possible restrictions that might have been enabled.
3.) Confirm there are no configuration profiles installed. Many similar profiles can prevent certain changes from being made on a device.
4.) Update your iPhone. This can usually help with unique issues, since updates include fixes. Just in case, this link can guide you through the update process: Update your iPhone or iPad - Apple Support
1.)Back up your device using iCloud or your computer.
2.)Plug your device into power and connect to the internet with Wi-Fi.
3.)Go to Settings > General, then tap Software Update.
4.) If you see more than one software update option available, choose the one that you want to install.
5.) Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do.
We hope these steps help you out. Thank you for using Apple Support Communities.