Your receiving bank can very quickly get notification of the incoming transfer, and 'spot' you an arbitrary amount (or all) while it _actually_ clears in the background.
Same day ACH has been available since 2017 and expanded in 2021. It's very slightly more expensive for the bank.
Whether or not the funds are made available mostly depends on how much the receiver trusts the transmitting account; even if it shows up the same day it still might turn out to be fraud a few days later.
