Better late than not at all - but, yeah, it is late.
Given the lengthy construction period of modern submarines, yes, time is very critical. I'm sure that Trump would've been amenable to a lease arrangement for, say, two of the U.S. 688-class attack boats... with a training detachment of USN bubbleheads. The Pacific is likely where such boats would be needed anyway, so it wouldn't really be a force reduction for the U.S. subsurface fleet (think combined cruiser squadrons, 1941-42). What Biden's "Central Committee" will agree to is anyone's guess.
At this point, I sure hope they're not trying to bootstrap a nuke boat program. Leasing from the U.S. or U.K. would be optimum, even newly-built boats, given the repair/maintenance that can be handled elsewhere if Western Australia (Fremantle, I assume) needs a year or three to prepare.