Exactly same problem with iPhone XS Max. I downloaded the iOS 14 beta the first date it was made available to public, (11th July 2020). Figured out in a few days it's a mistake done, that needs a lot of work to correct.
Issues found: My calls have dropped uncountable times, due to this network glitch APPLE has introduced for premium iOS 14 Beta users.
I have found my phone having no network at all for about 20 times, (and Its when I have noticed).
Only possible temporary solution as mentioned by most people is "reboot the iPhone" and keep checking for the network.
A few times phone hanged and rebooted automatically.
I wish the process of going back to iOS 13 was easier, but its not. So! sticking with this disastrous iOS 14 Beta updates, until lord Apple fixes this.
verma
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