Quote: I know MS edge has great codec support now as an alternative and can play most things with hardware decode, but native clients just run better and do more.
Not necessarily for now. The Edge does HDR better than JMP.
Quote:How come there aren't any desktop clients built for Windows Arm64?
Because of the popularity. Out of the whole 13% PC market share using an ARM processor, only 0.8% is the Windows ARM PC, almost all of the rest are Macs. The development team also lacks such device to even verify the proper functionality, and because it has low popularity the community also cares about this specific platform less, leading to low probability of a community contribution.