Cannot activate iPhone 12 due to missing Wi-Fi and old owner's iCloud information

I’m stuck on my iPhone 12, that I had to restore and then update which brought up old owners info and I have the info and it’s not showing up on his iCloud to be removed. When I tried to go hook it up to Wi-Fi it doesn’t give me an option to hook up to Wi-Fi. The bars at the top just keep going in and out in and out, and it doesn’t say SOS any suggestions?

[Re-Titled by Moderator]

Original Title: No WiFi/cant activate