Thanks for your feedback @eskimo. Considering that we only enroll in the Developer program for 2 days and have only one more developer besides me, the possibility of your suggestion that I somehow added that bundle ID in my individual team, accidentally, is high. May I ask how can I go to my individual team to check? I don't see any way I can navigate to that page.... Thanks!

There is no other team i can switch on the top right. However, I found something interesting on my Xcode: BEFORE I enroll to Apple Developer program, I use XCode for local development. And in the General tab of the XCode project, I use this Bundle Identifier I wanted to register now. However, there is a maccatalyst.com.XXX.YYY on Mac. @eskimo, do you think that is the cause? If so, how can I get rid of that and register in Developer > Account > Certificates, Identifies & Profiles > Identifiers? Thanks!