Hi, Lavenia A
Yes, I did the method before with non-Surface computer, but the result is the same.
My Surface Headphones 2+ can pair with my Friend original Surface Headphones 2+ dongle, so I think my Headphones 2+ no any problems. The problems is why new Dongle can't recognize in Surface App, but original package include in Headphones 2+ Dongle can recognize and pair. Maybe you can try to reproduce my issues in your internally. First find one Headphones 2+ which can pair with Surface USB link dongle, then find a single new Dongle(In Microsoft Store sale) and try to pair it, you will find the new Dongle can't recognize in Surface App. so I think need to resolve why new dongle can't recognize in Surface App but original dongle did. Sorry to say that and hope you can understand my concern and question. Thank you!