What the heck do I need to do to unlock the Legion Class mount?

Apologies if this has been covered, but I’m playing through the paladin class hall campaign on one of my alts, and I cannot figure out what else I need to do to get the quest to unlock the mount. I’ve finished the main paladin campaign, obviously. I also got the Defender of the Broken Shore and Nightfallen but Not Forgotten Achievements, which I thought were the only story prerequisties, but the Lord Greyson or whatever his name is still doesn’t have a quest prompt for me. What else do I need to do? It’s been so long since I did the class hall campaign on my main that I don’t remember what other triggers there could possibly be. Wowhead just mentioned the Broken Shore achieve, but then another post on reddit mentioned the Suramar achieve, but now that I have both of those, I still seem to be missing something.

So you will need to do all the order hall class quest, then the broken shore quest. As well as rep up with broken shore. Once you hit a certain rep lvl with broken shore and progressed your order hall you should see one of your class at the broken shore with a legendary quest.