I think the last time realm first achievements were a thing (for anything other than raids) was in Lich king, but I might be mistaken.
Since I wrote my previous comment, I thought about it, and there are advantages for starting earlier. Reaching max level gives you access to world quests, which can be a source of gear and reputation. It also leaves you more time to complete the weekly objectives before the next reset. If I recall correctly, last time (the launch of Dragonflight) you got an item you can use to increase the power of a piece of crafted gear.
For the average player it doesn't really matter, but for the world first racers, it might.
I've tried the remastered version on PS5, and it's rough. The atmosphere is great, the combat not so much. Personally, I've just watched a plot summary on YouTube, there are many, but I prefer Lady of Lore's.
Also, the game itself features a semi-conprehensive summary of the first game as well.