How do I resolve 'GarageBand can't be opened' error after upgrading to macOS Sequoia?

Last night, after I purchased a new laptop, I was finally able to upgrade from macOS Catalina (10.15.7) to Sequoia (15.4.1; the most recent operating system at the time of writing) and copy all my files and apps to the new laptop. Everything seems to be working fine, except GarageBand. Every time I try to open it, I get a prompt saying "the application "GarageBand" can't be opened". I checked for GarageBand updates in the app store, but there are no updates available for me. I also tried restarting my laptop, but it didn't help. What else can I do? I'm a little worried here, because I have a lot of unfinished projects and my previous laptop won't live forever... Any suggestion will be much appreciated!

[Re-Titled by Moderator]