I have the same problem with my iPhone 7Plus. I have just updated to iOS 14.2 yesterday morning and suddenly after the update, my phone have some problems with both Wifi and Cellular Data connectivity . The device now is like an useless brick, I cannot use any browsers or any apps. I have tried some recommendations below such as manually change the DNS or reset the network setting but it didn't work. Apple need to fix this bug and release a new update as soon as possible.
BHBHHBS
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