So Shadowlands is pretty crap, yes look at me I’m special, but some of the covenants transmogs are pretty cool. But the eorkings around them bogs my mind.
I ventured through the Night Fae Covenant and gained renowned 80. When this was done i had unlocked Garb of true spirit alongside Fae armor for all armor types, available for each of my alts. I then took one of my alts through Venthyr covenant and just hit 80 renown. But when icheck woth my alts, only Harvester’s court attire is available. My plate version of the venthyr armor set is available but non of the other armor types. Did i miss something?
Also, if i switch covenant with the 80 renown character, will i loose anything?
Same with Kyrian Colosseum and Ember Court.
I did everything from all Covenants on my Pally and can buy every transmog set from each armor type rewarded by the Ember Court, when it comes to the Kyrian Colosseum tho I can only buy the plate transmog. 
The system doesn’t work correctly. I have a problem with Venthyr transmogs too.
You don’t lose anything when you switch Covenant. Once you unlock a transmog piece or a mount or anything that is account wide it will stay on your account. Once you reach Renown 80 any cosmetics for that Covenant will no longer require being a member of that Covenant and nothing will change about it also.
I’ve been researching my issue and when it comes to covenant transmogs, multiple people report the same issue with Venthyr. Seems to be a Revendreth-probelm…