AXR4 is hands down the best sounding interface I’ve come across in ages. I previously was using Apogee Symphony I/O system also under thunderbolt and the difference is staggering,
I am positive development is underway for the interface because it really is a flagship product. The stability under Nuendo here is amazing - really no complaints. The only thing I do have complaints for is for the slow updates and the lack of information regarding 32 bit support which is not working under Big Sur - perhaps if more people email them things will change.