Change blog popup x to word "Close"

Add this code to the Custom CSS field on the Settings tab of your Blog widget’s settings:

[class*="Popup"] svg {
    visibility: hidden;
}
[class*="Popup"] button[class*="PopupClose"] {
    background-color: transparent !important;
}
[class*="Popup"] button[class*="PopupClose"]:before {
    content: "Close";
    font-size: 14px;
    color: #000;
}

Result: