I was going to reply with the same, but you and others have already said it, and probably said it better than I would have.
I still today get new people in AV. I tank through there. A LOT. Coincounter? "You ever did Fates Have It FATE?" "Yes." "Same thing, no ground markers, sidestep when he looks at you, I'll stun ranged attack." OR... The answer "No." "Run away when he does 100 tonz swing, no ground markers, sidestep when he looks at you, I'll stun ranged attack." First boss. "Grab a fruit on 2 stacks of debuff." Last boss. "Fruits on 3 stacks, kill pods asap."
It really doesn't take a lot even if you DO need to explain something to someone on most fights. Of course you can write your longer explanation too with specific attack names, emotes, etc. I certainly don't expect everyone to know AV or already watched a video of even this old of content. I sure as HECK don't expect anyone, or myself, to know something week of patch, but we go through every single time a new dungeon / raid / trial has been released. Unfortunately.