Multicam Clip only shows 1 angle (Final Cut Pro)

I’m editing a podcast in Final Cut Pro with 3 camera angles + a separate audio track. I can import all the clips, but when I select them in the Browser and create a New Multicam Clip, the multicam only shows 1 angle when I open it in the Angle Editor.

Things I’ve tried:

Importing clips from my external APFS drive (space available).

Selecting all clips in the Browser before creating the multicam.

Tested with shorter clips (same result — only 1 angle appears).

Used both “Automatic (audio)” and “Use Position” for synchronization.

What I want to do:

Create one multicam clip with all 3 video angles + my audio,

Or, if possible, create a multicam with 1 angle and then add the other clips as angles afterward.

Is there a proper way to add additional clips/angles to an existing multicam clip? Or am I missing something in the setup that’s causing Final Cut to merge everything into a single angle?

I'm using Final Cut 11

on Apple M3, 16GB on Sequoia 15.6.1 but working from hard drive.

[Edited by Moderator]