Left click the icon and inspect style in google chrome. That will show you what css is applied. Add that css to Page Attribute "CSS" > "Inline". The "!important" will force it to override other css. Original value was 20px, changed it to 40 so it is really visible, change it to your own needs.
.a-IG-controlsIcon, .a-IRR-button.a-IRR-sortWidget-button, .a-IRR-controlsIcon {
--a-icon-size: 40px!important;
}
On a side note, I would not play with this - changing the default UI behaviour of internal components will make your apps less upgrade proof which might cause you and the developers that come after you headaches :).