Ionic 4 Side Menu Without Shadow Hack

HTML

Use mode IOS To remove shadow on the side menu

    <ion-menu contentId="main-content" type="overlay" mode="ios">

SCSS

ion-menu {
    --background: transparent;
    ion-content {
        --background: transparent;

        ion-list {
            background: transparent;

            ion-menu-toggle {
                background: transparent !important;
            }

            ion-item {
                --background: transparent;
            }
        }
    }
}

Result