Note: this method is cool and easy, but might be performance heavy due to the Noise node usage!
Not the most efficient due to the Noise node, but might be useful. If you won't pin anything to the Position pin, it will utilize world position, so the decal will be kinda glitch-proof.
Material Domain: Deferred Decal
Blend Mode: Translucent
The more overlapping decals, the higher dirt intensity.