Unable to import BT.2020 PQ (9-16-9) HDR video in .mov format

Hi, I'm having trouble trying to import .mov files with the BT.2020 PQ (9-16-9) codec, but every time I try to import it into a project with Wide Gamut HDR, the file is greyed out and FCPX won't tell me why I can't import it.

I tried following the steps on Apple's site support.apple.com/en-ie/HT208229 with no joy.

Using Final Cut Pro X 10.4.8 on a 13 inch 2018 MacBook Pro 2.7GHz i7 16GB

Sample video file of Warner Brothers intro that I can't import (also attached):
mega.nz/#!mMgRgL6A!bTpmUf8pZXjJDPJhPo8lgDIlCFP5OcDA35ETBG7CbrY

If you don't want to bother downloading, here's the more info in Finder: i.imgur.com/RgqDHRp.png

And info from FFmpeg:

Stream #0:0: Video: hevc (Main 10), yuv420p10le(tv, bt2020nc/bt2020/smpte2084), 3840x2160 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn, 23.98 tbc (default)

Can anyone help out? Thanks!