so i finally figured out a solution that works for me.
in my game there is endless content randomly generated and scaled to 0 (destroyed).
besides, the player can also move stepwise (X pixel per touch)
currently, every second one new object is generated that contains 4 obstacles that can collide with the player, then they scale to 0.
what i do to solve the collision problem is that i set the new object and obstacle instance to a new layer every second.
this makes up to 18 layers. now, when i move my player, is substract it by one layer, else it also adds 1 layer per second.
this way i can check if the player position is on the obstacle position.
if both variables (player and obstacle) have the same "layer" variable, i check for collision.
i am not sure if this is a dirty solution performance wise, but it is at least very precise.
thx again for helping