@YumeYuki Its all here : https://learn.microsoft.com/en-us/learn/tv/
https://learn.microsoft.com/en-us/shows/browse?show_type=show&skip=30
For time being the archive can be found here until removed from the downloading servers : https://www.windowscentral.com/new-channel-9-index-page-gives-access-all-videos-you-could-ever-want