Trying to transfer Digital 8 videos to Mac

I have an old Sony Digital 8 camera (DCR-TRV410E) that still works and a box of old tapes I want to transfer to MP4s. I've transferred video from this camera before on my last Mac, but can't get it to work with this Mac (iMac (Retina 5K, 27-inch, 2019). I have a firewire cable that I tried running through an old LaCie hard drive and into my Mac. The Mac can see the LaCie, but not the camera. It doesn't show up on iMovie or HandBrake. It's not even on the list of iMovie for macOS supported cameras, although, as I said, I've done this a few years ago without a hitch. Any suggestions greatly appreciated.