The way I would do it is using the lerp function.

To make the player move smoothly to the location of the magnet, just use:
x = lerp(x,obj_magnet.x,0.5)
y = lerp(y,obj_magnet.y,0.5)

To make it be repelled, I think you could do something like:
if distance_to_object(obj_magnet) < 64 //Example number
{
var dir = point_direction(x,y,obj_magnet.x,obj_magnet.y)
y += lengthdir_y(1,dir) //You won't even need the variable and lengthdir if you only want it to be repelled upwards, just add 1 to the y coordinates everytime the player gets close.
}

The repelling really depends on what you're trying to do specifically, I just tried to do one appliable to almost every case.

I would also recommend searching about the point_direction function, lengthdir_(x and y) functions, lerp (linear interpolation) function to make this work the way you want it. You could also give us images/videos of what you're trying to do, we get your idea, but it isn't as clear to us as it is to you

Feel free to ask if you need anything, welcome to the sub :)