QComboBox and QAbstractSpinBox custom stylesheet affects arrow buttons

[sadeq]

Hello
I want to remove the gradient from these widgets to give them a "flat look" using custom stylesheet but it messes up the arrow buttons shape.
first if want to do this to a QPushButton I have to change the color and the border style also, if I edit the color only the gradient effect will still appear

                  QPushButton{
                     border-style : solid;
                     border-radius : 3px;
                     border-width : 0.8px;
                     border-color : white;
                     background-color:white;
                     color : black;
                     }

original look
, you can see the gradient and the popped up feel.
now, if I apply the same css to a QComboBox and QAbstractSpinBox the shape will look like this.
after css

intended look except for the color

I searched online for solutions and I found this in qtcentre forms and found this

pushButton->setStyleSheet("background-color: qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1, stop: 0 white, stop: 1 white);");

if i apply this to the combobox it will appear completely black on "fusion" style

is there a way to give a flat look to these widgets without messing up the look of the arrow buttons ?