Firmware update worked well and so far so good with sound and use. No problems at all w/ Mac Os Big Sur.
It's satisfying that Denafrips/Vinshine looking after existing customers like this. I do think Alvin and his team are very customer focussed and responsive. It's worth just as much as the quality of the product that the after service is so strong.
Just be careful with those little screws on the unit, as their thread is easily stripped.