Unable to unlock my Iphone 15 pro even entering correct passcode

I am not able to unlock my iPhone 15 pro even I enter the correct passcode. During several attempt " Phone Unavailable try after 1 minute, 4 minutes, 15 minutes message is showing on screen. Waiting period increases while trying again and again.

I contact apple online support. But they are also helpless for rectifying the issue.

Someone can please suggest a remedy for this issue?