Hi,

Try to add the following code snippet to the Custom CSS area in Theme Settings.

body .product-grid-item .btn-add > a:not(.add_to_cart_button),
body .product-grid-item .btn-add > a:not(.product_type_variable) {
	display: none;
}

body .product-grid-item .yith-ywraq-add-to-quote .button {
		position: relative;
    background-color: transparent;
    border: none;
    padding: 0;
    padding-left: 22px;
    color: #000;
    white-space: nowrap;
    font-weight: 700;
    text-transform: none;
}

body .product-grid-item .yith-ywraq-add-to-quote .button:hover {
	color: #333333;
	background-color: transparent;
}

body .product-grid-item .yith-ywraq-add-to-quote .button:before {
		display: inline-block;
    position: absolute;
    line-height: 18px;
    font-size: 16px;
    font-family: simple-line-icons;
    content: "\e04e";
    left: 0;
    top: -1px;
}

Regards