Button(KivyMD)- MDRoundFlatIcon I can't add radius to button and move icon right

Question

I'm working on an interface using KivyMD. In this work, I need to use DropDownMenu. I also created MDRoundFlatIconButton for this. I want to play with the dimensions of the button to fit the design I have, but I cannot add a radius to the button. Also, I can't get the "menu-down" icon right there.

I leave the design I need to create and the codes I use below. If you think that this design can be done in a different way, please write your suggestions.

.kv codes:

MDRoundFlatIconButton:
                size_hint: .25, .049 
                line_color: 0, 0, 0, 1
                text:"English"
                font_name: "assets/font/SF-Pro-Rounded-Light.otf"
                font_size: "14sp"
                icon: "menu-down"
                icon_color: get_color_from_hex("#000000")
                pos_hint: {"center_x":0.6729, "center_y":0.0441}
                theme_text_color: "Custom"
                text_color: get_color_from_hex("#000000")

must be:

DropDownMenu image

code output:

DropDownMenu image 2