Hey bud, you can register your device in the Samsung Members app itself. In the tabs below, click the 'get help' tab in the bottom right. Then top you can register the device using the imei and if it is able to you'll know that the device is legitimate.
I tried that but it said it's already registered, I guess it registered itself while I was upgrading to android 12. Anyways, thank you, if its already registered I think that means it's legitimate