White hits are surprisingly effective. It’s good to have some sort of way to track threat, but also, you can only hit so many targets per GCD (like 1)., and sunder costs rage, so use accordingly.
This old (Classic 2019( low level tanking guide aimed at new warriors to Classic is a decent read:
Level 20 is a great time for Deadmines. Can even go a little earlier, but 20 is about right.
Dire maul isnt out yet.
Nobody refers to instances in Diremaul as DM anyway. I’ve seen some people saying “LFG SM” in a similar manner, but they must be new to the game, as the instances are not all the same level, so people specify.
There is a subset of (apparently) Alliance (only) players who insist on calling Deadmines VC, presumably due to the Van Cleef questline and to a reference in the original WoW paper manual, but it’s incredibly uncommon on the Horde side (I don’t recall any time even seeing it personally, anecdotally, and it’s also not particularly common in my experiences playing Alliance).