They are not “fake”
They are MTK M6739
They may or may not work for VoLTE depending on the carrier certification check for your provider.
We are investigating the “no carrier check” config and I’m hoping that this is included in this watch firmware so that I can pull it and apply it to some other models.
After enabling developer options and usb debugging, the engineering app should work.
What is most important is that more people use the app linked earlier, lock it to LTE only and test voice calls.
So far I believe it has only been tested on EE in the UK.
We need more.
Until I get my test sample.