The I2S over HDMI format is frustrating because there really isn't a set standard for the pinouts that is adopted and used by every brand. Instead we get a bunch of different configurations to the point where you are only guaranteed compatibility when using the same brand for transport and DAC.
Sometimes they don't work at all due to different formats. Other times I've experienced playback that sounded weird, or out of phase, or worked for PCM but not DSD. It all comes down to how each brand does their configuration. If I remember correctly I think Denafrips uses the same style as PS Audio and several other brands for I2S. So there should be at least some options when mixing brands. I don't know about LAIV yet though.
I would just try a regular HDMI cable that you probably already have laying around somewhere. See if you get sound at first, then listen for any distortion or choppy sound, that sort of thing. Then make sure you can do hi-res and DSD without issues. If all that seems to work then you've passed the test, and you might consider trying a nicer HDMI cable.