I posted the issue on Reddit and someone who is an admin said they submitted it and got this promising response:
Good news.. I’m an admin and logged a ticket with MS. This is their response:
Following our discussion, I have consulted with my team regarding the issue you reported. We have received similar reports from multiple Mac users experiencing difficulties with the keyboard shortcut for text selection in the Outlook Web App on Mac OS. This issue was first identified on April 2nd, 2024, and I am pleased to inform you that our team at Microsoft is actively working on a resolution. Once the fix has been developed, it will undergo testing before being deployed to all affected tenants. While we do not currently have an estimated time of release for this fix, please be assured that we are committed to resolving this issue as swiftly as possible. We appreciate your patience and understanding during this time.