How do I confirm successful remote erasure of an iPhone from iCloud?

I traded in my iPhone 12 and didn’t have my apple password. I went home and remotely erased my phone from iCloud. I got an email from apple saying it was being erased. The next day I went and checked the phone at the phone place and it was on the white welcome screen, but it said it was locked to my iCloud account. I removed the device from my apple account that day.

Was my device actually erased though? I’m paranoid that it might not have been, do you get 2 emails from Apple about it being erased? Or does the one indicating it’s being erased indicate it was successful?

[Re-Titled by Moderator]