Seattle is the answer there to avoid the CA state tax, cheaper rent / cost of living. Check levels.fyi for entry level SDE1 jobs / salaries. $160-190K USD total comp. Rent (usually your biggest expense) for a studio / 1BR is about 1.5-2K/mo. Tax brackets are quite different (that entry level job might push you into the 32% marginal rate, while in AU, that would be the 45% marginal bracket).

Mid career you could be earning 3-6x your Aussie salary post tax (depending on the exchange rates, life choices etc.), particularly if you find yourself earning significantly more due to stock appreciation.