Code

<button type="button" class="btn btn-primary" data-bs-toggle="modal" data-bs-target="#editorModal">
    Open editor
</button>

<div class="modal fade" id="editorModal" tabindex="-1" aria-hidden="true">
    <div class="modal-dialog modal-lg modal-dialog-scrollable">
        <div class="modal-content">
            <div class="modal-header">
                <h5 class="modal-title">Edit content</h5>
                <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
            </div>
            <div class="modal-body" id="editorModalBody">
                <div id="entry-bootstrap-modal">
                    <p>Start typing after the modal opens.</p>
                </div>
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Close</button>
            </div>
        </div>
    </div>
</div>

let app = null;
const modalEl = document.getElementById('editorModal');

modalEl.addEventListener('shown.bs.modal', () => {
    app = Redactor('#entry-bootstrap-modal', {
        bsmodal: true,
        scrollTarget: '#editorModalBody'
    });
});

modalEl.addEventListener('hidden.bs.modal', () => {
    app?.destroy();
});