New iPhone 12 only works around Wi-Fi

I'm so sorry, but what a ridiculous answer.

I have an iPhone 12 Pro since I got the same problem. I contacted Apple support.

I reset the network settings. I reset the modem settings. I installed it as a new iPhone. It didn't work.

I turned off "private address" in wifi settings. I have 100mbits internet. I get 10mbits hard. Average 0.50mbits.

Disgrace. I have to use cellular at home.

I think it's a hardware problem. iPhone XS, iPhone 6, iPad Air 3, iPad Air 2 and iMac are all connected to the same network.

I feel your pain on the iPhone 12 only working around WiFi. I didn’t spend all this money on a new phone to only use it at home!! Apple has been absurd with not correcting the problem and calling back when they were supposed to I have spoke to eight supervisors all of them had different things to say blaming my carrier! Here is the deal if you can’t help me and don’t want to help me don’t screw me around to where I couldn’t return my phone to my carrier because the two weeks were over!! Feeling sad that this big of a company can’t help with having major problems like this! Oh and it gets better, I had one supervisor say it was my MacBook causing the problem only for her to give me all these steps to screw my MacBook up beyond repair and she hung up BECAUSE HER SHIFT WAS OVER! For Gods sake what happened to good customer service, making sure the customer has a working product!!

pathetic I feel like I should just go back to rotary dial phone and forget cell phones because no one is willing to help meaning Apple does not give a crap! Sad sad!

Ask your carrier for help.

Who sends the cell signal to your device?

Thought so. It's not Apple.