You can't use lerp() to do acceleration. You have two options. One is to use a third party plugin like litetween to do the easing or you can do it with math.

For the math route to do acceleration you need to keep track of the object's speed. Then using this formula to calculate the stopping distance:

stoppingDistance = (speed^2)/(2*acceleration)

You could do this:

global number acceleration=100

global number velocityX=0

global number velocityY=0

global number targetX=0

global number targetY=0

global number angleToTarget=0

system: compare distance(sprite.x,sprite.y,targetX,targetY) > (distance(0,0,velocityX,velocityY)^2)/(2*acceleration)

set angleToTarget to angle(sprite.x,sprite.y,targetX,targetY)

add cos(angleToTarget )*acceleration*dt to velocityX

add sin(angleToTarget )*acceleration*dt to velocityY

Else

set angleToTarget to angle(sprite.x,sprite.y,targetX,targetY)

add cos(angleToTarget )*-acceleration*dt to velocityX

add sin(angleToTarget )*-acceleration*dt to velocityY

Every tick

sprite: set position to (self.x+velocityX*dt, self.y+velocityY*dt)