Bootstrap CSS class .modal-static

    <button type="button" class="btn btn-primary" data-bs-toggle="modal" data-bs-target="#staticBackdrop">
        Launch static backdrop modal
    </button>

    <div class="modal fade" id="staticBackdrop" data-bs-backdrop="static" data-bs-keyboard="false" tabindex="-1" aria-labelledby="staticBackdropLabel" aria-hidden="true">
        <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
            <h5 class="modal-title" id="staticBackdropLabel">Modal title</h5>
            <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
            </div>
            <div class="modal-body">
                 Lorem ipsum dolor sit amet consectetur adipisicing elit. Soluta, distinctio!
            </div>
            <div class="modal-footer">
            <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Close</button>
            <button type="button" class="btn btn-primary">Understood</button>
            </div>
        </div>
        </div>
    </div>