Hmm okay can't I use one adepter for Arduino's and motors? I write this 4A+4A+2.3=10.3 because If I use 1 adapter for motors and Arduino same time. I will need 36V 15A and I can use 300W buck converter with these. (I am not thinking this method but it is possible right.)
And I looked HX711 Datasheet It says
normal operation < 1.5mA, power down < 1uA
• Operation supply voltage range: 2.6 ~ 5.5V
I am thinking 1.5mA is too low