Why do all fifth generation fighters (J20, F22, SU57) use Trapezoid wings? It seems that trapezoid wings are used by all fifth generation fighters (although the wing of J20 looks quite like delta wing), but why? What made a trapezoid wing so attractive? Why don't they use other forms, like the swept wing on SU27?
Trapezoidal wings have advantages and disadvantages:


Better performance than delta wings at transonic speed
Good stealth performances
Flaps can be easily used.
drag reducing
better Lift/Drag ratio than delta wings 


The problem is that they stall at much lower angles of attack than delta wings.

Edit:this problem is overcome using leading edge,LERX,and/or canards