You absolutely, positively, without a doubt, must check out
Skills with Phil YouTube Channel
https://www.youtube.com/channel/UC0Q...NF9k9fiNXkqn_w
also
Bike Radar has some decent stuff
https://www.bikeradar.com/advice/skills/
as does Global Mountain Bike Network
https://www.youtube.com/channel/UC_A...gea0i4UtpD99Gg