Before getting into Dao, it’s important to understand about Law first. And while each term corresponds to some ontological differences, each level could be called Dao from time to time as they also symbolizes the Path that each characters took, such as the Path (Dao) of Fate, Path of Sealing, etc.
In conclusion, Law-precisely Regular Law-is a type 2 Concept. Scaling for Innate, Heaven, and Primordial Law aren't good enough yet, though they are superior than the Regular Law.
Dao is a type 1 Concept.
Grand Dao Source is a Greater Type 1 Concept.