The only system that works is a low profile parallelogram that slides
underneath.
You lift the handle at the front, the parallelogram expands upwards
lifting the appliance off the floor. The parallelogram action stops
just after it goes past vertical - ideally a press-to-release cable
latch could be implemented to lock it.
The underside has large PTFE sliders or rollers.
The problem is accommodating washing machines, cookers & freezers of
over 120kg.

A sack cart isn't ideal - the ledge does not extend far enough under
the appliance (instead hooking under the front and burying itself in
motor & hoses underneath); additionally most cars are not strong
enough to handle 120kg+ machines. The fundamental flaw is you can't
tilt sufficiently due to the proximity to low kitchen worktops so you
end up half lifting, half dragging the thing out of its hole.


The solution is for manufacturers to simply fit a full width roller on
the rear of heavy appliances, then the front has castors or spherical
sliders which are simply "disintermediated out" by screw down
adjustable feet which are relatively common. Perhaps one area where a
good few lawsuits for injury would actually (uniquely?) have a benefit
for society. Marketing evidentally get someone else to pull their
machine out, no doubt whilst they play with coloured bricks.