No. Guam and Australia are separated by thousands of kilometers of Pacific Ocean and belong to entirely different geopolitical spheres.
Both are "in the Pacific," both have tropical/coastal vibes, and both appear on Asia-Pacific travel itineraries. But politically, culturally, and geographically—they're distinct worlds.
Australians visiting Guam need a U.S. ESTA or visa; Guamanians visiting Australia need an Australian ETA or visa. Different currencies (USD vs AUD), different driving sides (right vs left), different everything.