As far as Xenosys Vex goes, his guides focus on EX primals and raids. They aren't the best guides ever nor are they for everyone, but the guides are detailed enough for viewers to grasp significant mechanics and show opportunities on how parties can maximize dps if they work as a team. Teamwork abilities includes healers supplementing dps, dps players using enmity lowering/tranferring abililities, tanks using defensive abilities, etc.

His Sophia EX guide really helps keeping the tilt mechanic simple:

https://www.youtube.com/watch?v=NdagMVPk9U0

His Alexander guides were great too:

A12S:

Guide: https://www.youtube.com/watch?v=H8REZtPcchU

8 tank clear: https://www.youtube.com/watch?v=50kFN0bnXBQ

He only has one guide out for Omega Savage afaik, but here is the link anyway (For O4S):

https://www.youtube.com/watch?v=yJyf07dOxZI