I love me some Total Warhammer, you know this.
However it occurred to me yesterday, as I restarted my Ogre campaign from scratch, that I think I have restarted every campaign I have played in the franchise (at least in Mortal Empires/Immortal Empires; the "story" campaigns are usually small and straightforward enough that even if you fumble the early game, they're over before it matters).
While the basic mechanics are roughly the same for any faction, they each have some unique mechanics that change the way they play in big ways. And then you add in the differing strengths and weaknesses of the units, you're sort of learning all over again for each new race.
I've clocked in around 300 hours in the Total Warhammer franchise overall, which is a lot of hours in general, but also feels like barely scratching the surface of a game like this. I know some things, but I'm not at a place where I've memorized all of the kill traits for opposing Legendary Lords, or instantly know an enemy's army composition/stats just by glancing across the field. I have not played every faction.
So in that regard, I guess I play a training campaign each time I start a new faction in Total Warhammer. Take Ogres for example. The game (and youtube videos) can TELL you that they use camps to set up bases anywhere you want instead of relying on captured provinces to build high tier structures, in a way that is wholly unique to the Ogre Kingdoms.
But it provides no applicable insight on where you want camps, when to build them up and when to use them as temporary support for your raiding armies, which buildings you want and in which order, etc.; the elements I can only start to dissect seeing it in action.
So it might be turn 60 before I realize "Oh wait, these units aren't holding up, I should have phased them out/not upgraded them as much" or "Shit, I've built up/invested in this camp that would have been much better strategically placed over here."
So usually around turn 120-140 I look at the situation with the benefit of my newfound applied knowledge, and say "alright, that's enough practice."