Windows 10 & Xbox

I purchased the Digital version of the game so it is installed on my xbox one s & window 10.
So, how come when I progress through the game on windows 10 this progress does not show up on Xbox and visa-versa.
Like, on XBOX I have earned zillions of credits but on Windows 10 I have a minimum amount.
Whichever platform I play the game on when I go to the other platform I have to complete the same races over again. It’s the same with Barn finds etc.

I don’t know, maybe it’s meant to be this way, but it sure is becoming boring doing things twice, especially the Barn finds.
I use the same sign-in & have the same details on both devices.
It was not like this with Horizon 3, the xbox & windows 10 synced data between each device perfectly & still does.