How to convert old .mov files to format that is viewable?

I have some old .MOV files that will not open in QuickTime (OS Ventura 13.3). I get the error "This file contains some media which isn’t compatible with QuickTime Player." My understanding is that this file has an old CODEC setting that is no longer readable. It will play the audio only, no video.

How can I open the file to save it as an updated format? I have tried opening it/importing it through iMovie, with no luck. iMovie doesn't seem to recognize it (it is greyed out/unclickable). My end use is to upload the video to my Adobe Portfolio site. Thank you.