I started driving in a 1930 Swallow (the first Jaguar) with a non-synchronized shift (appropriately called a “crash” box). Definitely only one foot, unless you were changing gear (even that could be done using just the gas pedal, if you got the revs exactly right). Using two feet either wore out the front brakes (the only ones connected to the pedal - by a simple cable; to use the rear brakes you had to use the parking lever) or the clutch thrust race (which needed frequent use of the oilcan to keep it lubricated). So I’m a single-pedal guy. Or was until recently. As a result of a foot injury, I don’t trust my right foot to give enough pressure on the brake, so I now drive with both feet - but I am very careful not to let my left foot “ride” the brake pedal. That’s a recipe for accelerated wear or brake failure due to overheating - not something to be experienced in the canyons here in Utah!.