Like 2-3 times to fill an engine?

on the pumps.

Just like customers who pay cash now have to go inside and tell cashier how many gallons and cashier takes their money and sets pump for that number of gallons to be pumped out by customer.

do that?

currently.

They could probably do that with some sort of software.

... and gas pumps were entirely mechanical. There were all sorts of ad-hoc ways of dealing with this. Mostly they replaced the mechanical counter and crudely punched extra slots in the metal bezel framing the numbers.

It ought to be easier now that pumps are electronic. It's past time to get rid of the 9/10 of a cent measure.

...changed the gearing in the pump so 56 cents now only delivered a half-gallon.
Then, inside the glass, they would have a card over the "per gallon" words that said "per half gallon".
With modern flow control devices, they could probably just change the programming to "half-gallon" and put a sticker on the pump.

...they'd have to sell by the quart.
But, it won't. There will be torches & pitchforks in the streets before gas exceeds $10.
The Failure & his minions will admit defeat even if their superrich benefactors have to threaten to back impeachment & conviction.
$10 gas will cripple the economy & nobody makes money. The oligarchs seeing the scope of the fortubes reduced will be pissed.

They sold gas by the litre to accommodate the physical shortcoming of the pumps.

And the pumps should work,

where are they now? Or was it never really about gas prices and it was really about trying to turn people against Biden by planting the idea in their head that gas prices were high (when they weren't) because of him?