Coming home, with offshore income.

Australian citizens and permanent residents don't need FIRB approval regardless of where they're currently living. The state-level foreign-purchaser surcharges also don't apply (NSW, VIC, QLD, SA, and TAS exempt citizens, permanent residents, and ordinary-resident NZ-Special-Category-visa-holders, even if currently overseas).

Lender side is harder. Most retail lenders want PAYG income from an Australian employer to underwrite a residential mortgage. Foreign-currency income is sometimes accepted (HSBC, ING, and some specialist lenders) at 80-90% of converted amount, with tighter LVR caps (often 75%). Expect 2-4 weeks longer underwrite vs domestic borrower.

Tax position: while abroad, you may have been a non-resident for tax purposes, affecting CGT main residence treatment if you owned property in AU during that period (the main residence exemption is partially restricted for foreign tax residents under post-2019 reforms). Any new purchase resets the clock.