[RockerC]

As I understand, the 'older' Amlogic S905X2 SoC/chipset in this dongle does not support AV1 hardware-accelerated video decoding.

YouTube has used AV1 for quite a while now, and Netflix recently started to stream in this format for compatible devices.

Yes - but both Netflix and YouTube also serve content in alternative codecs - and if this devices has been being developed for a while to get kinks knocked out of it etc., then it isn't going to be bleeding edge tech.  SoCs that support AV1 are only just beginning to appear - so it's not unexpected that this device isn't based around them?

I was actually surprised that Google did not choose an SoC that supported AV1 because both Netflix and YouTube not only support it but these companies are also major backers behind that new video codec.

S905X4 SoC is available since Q4 2019 and it's pin-compatible with S905X2, S905X2 and the S905D3. Google could have made up for the extra money it might cost with future internet bandwidth fee savings.

It would not really require any development effort from Google's engineer to replace the S905D3 SoC with an S905X4 SoC since it is pin-compatible and in the same series from the same manufacturer.