Ok After struggled for a while finally I figured out how to use Garmin VIRB Edit (MacOS, 5.4.3) to edit videos from gopro7 black. So I write it here just in case others face the same problems and can't find solutions.
1, After you import your video, optimize it. Or you will see error like "unknow error happened when playing" or something like this. If you see this error after optimize it, try to reinstall VIRB Edit. I don't know why but it works after I tried.
2, Change your Gopro 7 black (havn't try other devices) videos to HEVC 264, but not HEVC. Or you may see error when you import the video.
Hope this will help you.