I had trouble at first but was able to get this (kind of) working with my X-T4.
MacBook Pro 2017 (USB-C ports)
Mac OSX Catalina 10.15.7
Zoom v. 5.2.0
USB-C to USB-C cable (worked with the cable that comes in the X-T4 box and also a generic cable)
X-T4 firmware 1.10
Mac app: FUJIFILM X Webcam 2
My mistake was that I was waiting to see the camera recognized by the Webcam app before connecting to Zoom.
Turns out you have to launch Zoom first, select "FUJIFILM X Webcam 2" as the camera (from Preferences > Video) and THEN (and only then!) the webcam app will recognize the camera.
NOTE: It's also necessary to have the latest version of Zoom. Earlier versions did not allow for virtual camera input, which this relies on.
I say "kind of" working because the video is unusably jerky and delayed. Any advice on that?