Matrix Table - "At Least" Validation

You can use the following JS to implement it:
Qualtrics.SurveyEngine.addOnReady(function(){
that = this;
var init_ques = this.getQuestionTextContainer().innerText;
this.disableNextButton();
this.questionclick = function () {
var a = that.getSelectedAnswers();
var ch = Object.values(a).reduce(function (a, b) {
return a + b;
},0);
if(ch >=3){
that.enableNextButton();
that.getQuestionTextContainer().innerText = "Okay to proceed";
} else {
that.disableNextButton();
that.getQuestionTextContainer().innerText = init_ques;
}
} 
});

Demo here.