Fortress versus Necropolis.

Stun him with Orson on week 3.

Well, it depends on the map.

As mentioned above, it is very beneficial for the Dwarf to develop both Light and Chaos simultaneously. This is where the catch lies. It is very easy for him to protect his troops from Armageddon, while the damage from the Fire Lord will be significant. Therefore, Light must definitely be chosen in the late game against the Dwarf. And also, reduce his defense – SA plus artillery plus the right upgrades – and no leadership, even with a Knight set, will help, not to mention Rune Harmony. I didn't come up with this tactic out of thin air; it has been tested against a good player playing as the Dwarf, and the Dwarf and Necropolis each had only one castle. But there is a condition – there must be a Mentor on the map; otherwise, the chance of developing in the right direction is extremely small.

And of course, I agree with you that the Dwarf needs to be eliminated while he is still small. Unfortunately, not every map allows this.