That’s odd decision - which should be clearly stated at the first place. First BETA early access I downloaded from Insider Hub, but I played it via my favorite platform (Steam). I didn’t realise, that the situation could change.
EDIT: I first preordered FS2020 from Microsoft Store, but I cancelled it because I read, that I can play early access via Steam where all my games are.
Anyway, thank you for the information. 