Re. dead keyboards
I have the opposite problem, about a million USB dongles for old keyboards and mice.
Re. bluetooth problems with Windows 10, I feel your pain.
It seems to be that the "old" adaptors worked fine but something about the high density components makes it more flaky than usual.
Maybe I can do some more research and find out what Microsoft changed to make the Bluetooth flaky because it works perfectly on 7 with the same machine.