Yes they are.
Every season gladiator mount grind is added, and it is limited time.
scarab lord was also an insane grind, and was very much limited time.
Long strange trip literally takes an entire year, and yes it is limited time, cause if you don't finish part of it, you gotta wait another entire year to try and get it again. and for some of them, they do take a LONG time.
also wow, longest grinds are mostly for clout and have minimal rewards, almost like this.
also I mean, I literally made a massive list of them.
https://www.youtube.com/watch?v=A7gHGkc1IZo