Ref

only fix RTL

If you want to keep messages in left and just fixing RTL issue, add the following script to workspace/settings/layotu/Custom CSS

.rcx-message-body {
  text-align: left;
}

improve message box and fix RTL

To make the RTL languages ot start from right to left, add the following script to workspace/settings/layotu/Custom Scripts in the Custom Script for Logged In Users:

function setAutoDir(){
    $("div.rcx-message-container[dir!='auto'],div.rcx-message-body[dir!='auto']").attr('dir', 'auto');
    $("textarea.rc-message-box__textarea[dir!='auto']").attr('dir', 'auto');
}
setAutoDir();
var elementCount = $('.rcx-message-body').length;
var observer = new MutationObserver(function(mutations) {
   var newCount = $('.rcx-message-body').length;
   if (newCount != elementCount) {
        elementCount = newCount;
        setAutoDir();
    }
});
observer.observe(document, {attributes: false, childList: true, characterData: false, subtree:true});