Bootstrap 5 does not require jQuery but works alongside it. Listen to Bootstrap events like show.bs.modal with jQuery's on(). Access Bootstrap component instances with bootstrap.Modal.getOrCreateInstance($('#id')[0]).
jQuery + Bootstrap 5
// Bootstrap 5 uses vanilla JS, but still works with jQuery
const modal = new bootstrap.Modal(document.getElementById('myModal'));
$('#openBtn').on('click', () => modal.show());
$('#closeBtn').on('click', () => modal.hide());
// Listen to Bootstrap events
$('#myModal').on('shown.bs.modal', function() {
$('#firstInput').trigger('focus');
});