There's a 'Progenitor' commander, but functionally it's just a bit more anthropomorphic than the others and otherwise identical. One of the factions believes 1) they must be eliminated at all costs, and 2) they are even now preparing to attack and destroy the robots.

Absent Aliens: The only thing known about the Progenitors is that they came before the commanders.

Played straight with the Ragnarok (which can also explode planets, but is slow to build and takes time to charge as well, making it easily destructible) and the Catalyst (requires a metal planet and 5 catalysts to be built, so you probably could have won twice by the time you fire it).

However, without a way to move the commander away it's an instant win and reduces the potential places they can hide, on top of being a no-questions-asked instant destruction of a planet, all defences be damned. which also automatically destroys a lot of precious resources and build space, to say nothing of the cost of building the engines required to move a planetoid.

Colony Drop often completely destroys not one but two planets.

Nukes can 2-hit commanders and destroy armies, but are instantly defeated by anti-nukes however, they can be launched anywhere in the solar system and are comparatively cheap superweapons.

The Helios titan is vulnerable to orbital defences, but is a rapid transporter that is otherwise hard to destroy and provides its own air support plus it's movable, unlike ground-based stargates.

Atlas/Zeus/Ares titans are slow and expensive, but can easily annihilate massed armies and bases on their lonesome, and can be built surprisingly early.

Awesome, but Impractical: Averted with most of the titans/superweapons, which each have their own niche.

This game provides examples of the following tropes:

Planetary annihilation titans factions