If you are using YouTube, you can add the following parameters at the end of your URL to make it autoplay ?autoplay=1&controls=0&&showinfo=0&loop=1 so the final URL should look something like this: https://www.youtube.com/embed/HBDa22mdC8M?autoplay=1&controls=0&&showinfo=0&loop=1

However, in my experience, the loop feature is very flaky, it works when it wants to. So I would recommend, creating a playlist and having the same video in it like a 100 times.
You can also disable any interaction with the player by adding the following JS code:

document.getElementById(this.questionId).style.pointerEvents = "none";

Furthermore, you can hide the video from the participants by adding

this.getQuestionContainer().hide();

These need to go in addonReady method of your Video question.
Lastly, to display the question after sometime, you can use the following JS code:
Qualtrics.SurveyEngine.addOnload(function()
{
    this.getQuestionContainer().hide(); // Hide the question as soon as the page loads
});

Qualtrics.SurveyEngine.addOnReady(function()
{
    var delayTime = 6000 //This is the time of delay
    var that = this;
    setTimeout(function(){that.getQuestionContainer().show()}, delayTime); // Function to show the question
});
This needs to go into the JS of the question you are asking.

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