CD reset came much much later, could debate it's different WoW when that happened. It was definitively a choice they made to have certain skills have extremely long CD's. Which could also mean that makers of the game didn't want the long CD's gone and made menial with reset until much later. Long CD skills are big resources that should be used with caution. Yes, it's 2025 now, but you're playing a game that's emulating how things were in 2007. I only use Wowhead for their dressing room when I'm trying to find interesting transmogs. When I was learning raids, or their more precise tactics, I learned through our GM/RL's. We did attempts, just like you, and often without that big CD being available from the get go. Progress was made even without those big CD spells. Sometimes we simple AFK'd for those CD's. It's amazing feeling when you can put on a good song and listen to it, relax a bit before going tryhard sweatlord on some PvE content.
Yeah, I don't play on Onyxia. What was your point? You think I haven't done any progression ever? Or that I couldn't possibly know anything about Onyxia without ever setting my foot on that realm? Do you think I couldn't apply my vast knowledge and experience on this matter? You think I haven't picked up on WoW design choices, such as long CD skills?
Throwing bodies at boss and hoping things are better this time doesn't do **** if you don't understand, no, if you don't comprehend the boss mechanics, or raid tactics. That's when you actually talk about the fight tactics and mechanics. Or advise another plan to deal with the situation. That takes time.