Change background icon

To remove the background delete the class in the column settings

To change the icon to your own you need to upload a new icon and add the custom style

.custom-container-max-with-with-icon:before {
    background: url(https://yoursitename.com/wp-content/uploads/my-new-icon.svg) !important;
    background-repeat: no-repeat !important;
    opacity: 0.1;
    top: -6.875rem;
    left: 19.375rem;
    width: 29.25rem;
    height: 11.3125rem;
}