Work Around Found! Requires GamePass and ability to stream FH4 on another device
At the moment I have found on Game Pass, if you open a stream into Forza Horizon 4 on another device rather than on my Xbox One, then when I go to import my Vinyl Groups from previous titles they all appear. So I went through on Streaming and imported all the Vinyls I thought I might want and saved them in FH4. Closed the streaming and opened up on Xbox One and they’re all there saved in FH4 to use.