HDMI eARC capture based on IT6612x or similar

Have been looking for a flexible solution to get full audio capture from HDMI 2.1 eARC. There are several low-cost boxes to have an eARC audio extractor that split into 4 lane I2S or S/PDIF and such. ( e.g. OZV8E, HDCN0047M1 boards )

Would be awesome if there was a Raspberry board that would all channels with TDMS over Raspberry I2S input or even maybe over USB 3.0 input.

The solutions for doing this are scarcely documented, because it's HDMI, but a few options that I've come across on Github and elsewhere is ITE IT66121, which has Linux/Android drivers. ( possibly also their IT6622 / IT6620BFN ). There's also Lattice SiI9437/SiI9438, but even less references for the designs.

A few other chips in similar splitter boxes seem to be MS9331, ES9023 and as is tradition, none of them have public datasheets or much references around.