My question is: will the liquid get drained this way? I think it will (all
except for the portion in the sag). Just checking my thinking.

I do things like that all the time, the main thing is the the drain end
is lower then the origin. Example; draining a water-bed or aquarium ,
the hose runs down to the floor, up the wall out the window, the down
to a flowerbed, works like a charm