Ozzy if you’re willing you can try doing the following:
Take the vivid and run your cable that works with your Oppo and attach it along side the length of the vivid. You should see an improvement to the your video. Also use the provided power supply when putting this together. Give it 10 to 20 min. to do it’s thing.
It’s not going to be as good as going through the unit, but it will give you a sample of what it can do to your signal.
The cable used inside the vivid should have worked it is quite capable at 8k.