Yes, I have a function that highlights unanswered matrix rows after 'Next' is clicked if you are interested in purchasing. It works with either "Force Response" or "Request Response". It is compatible with all Likert Matrix options: Mobile Friendly, Transposed, and Position Text Above. It automatically detects which options are selected and adjusts accordingly.
Screenshot:

https://community.qualtrics.com/XMcommunity/discussion/comment/32225#Comment_32225Hi TomG, I was wondering if I could request your help with implementing your code on my survey? This is exactly what I have been looking for! Many thanks, A.

https://community.qualtrics.com/XMcommunity/discussion/comment/41521#Comment_41521The code is proprietary. I sent you a message.

https://community.qualtrics.com/XMcommunity/discussion/comment/41526#Comment_41526Hi TomG,
May I also request your help with implementing your code on my survey?

Hi TomG ,
Can you please also send me the detail on how to use your code? Thanks

https://community.qualtrics.com/XMcommunity/discussion/comment/41526#Comment_41526TomG Hi Tom. I am looking for thí solution. Can you help me with that please. Thank you.

I am looking to change the text within the "Response Requested" box so that it contains a custom message. I am wondering if this could be achieved by editing the code that TomG has referred to. If so, could I request the code or have some pointers?
I tried to use this code, but it only seems to work when I have "Force Response" on as opposed to "Request Response."
Qualtrics.SurveyEngine.addOnReady(function(){
    const qid = this.questionId;
    tot_choices = Qualtrics.SurveyEngine.registrygqid].getChoices().length;
    var sel_choices = 0;
    
    that = this;
    this.questionclick = function(){
        sel_choices = that.getSelectedChoices().length;
    }
    
    document.querySelector("#NextButton").onmousedown = function() {check_answers();};


    function check_answers(){
        if (sel_choices == tot_choices){that.clickNextButton();}
        else{
            //Selecting Okay will result in continuing
            if (confirm("Custom message here") == true) {
                that.clickNextButton();
            } 
        }
}
});

I've updated my function to optionally override the bullt-in Qualtrics error messages for force response and request response.

https://community.qualtrics.com/XMcommunity/discussion/comment/47252#Comment_47252Could you share this?

https://community.qualtrics.com/XMcommunity/discussion/comment/48070#Comment_48070It isn't free. Details on the function are here.