iPhone 12 Pro movie imported into iMovie is very washed out
I have a video I shot on an iPhone 12 Pro, copied to my computer as a Quicktime .MOV file. It plays fine on my Mac Mini, but when I import it into iMovie, the clip appears very washed out. Color seems to be missing, and the color-correction tools in iMovie won't let me get it right. It seems as if the brightness is just turned way up, but using the color correction tools to turn the brightness down doesn't fix the problem.
Is this something wrong with iMovie? Any workaround?
Mac mini, macOS 10.15