Not strictly true, like I said, any graphics card in the last 15+ years with DVI ports can be used for HDMI transmission, but they fully meet the DVI spec's requirements as well, and thus are compliant with the DVI specification. I think what you meant is that DVI ports are only sure to be compliant with the DVI spec and therefore are not
guaranteed to have these additional features. Which is true, but being compliant with the DVI spec doesn't preclude these capabilities, so it's not correct to say that compliant DVI devices don't support this, or that devices supporting it are non-compliant. And the reality is that all graphics cards in the last 15+ years will support this, as I said. So no need to be cagey about whether it might work or not
I used to run a 4K 60 Hz display at full HDMI 2.0 bandwidth (with audio as well, by the way) from my RX 480's DVI port with a passive adapter, and before that I had audio through DVI to HDMI on my GTX 780 Ti and my GTX 580 before that. I think support for this goes back to the GTX 200 series.