I've been trying to do some video editing today in the desktop app (Macbook, Sequoia 15.3) but had to give up because it kept freezing and I had to keep force quitting.

Also the icon does not appear in the system tray at the bottom of the screen - just a tiny grey dot - so the only way I can find of shutting it down is via Cmd + Option + Esc and then Force Quit.