problem with jquery 3.5.1 in footer

GREAT… thank you very much. It opens my mind.
I’ve tried to translate this eventListener in bind jQuery version, but I can’t.
So I modified the FancyBox Jquery to read directly wp block < a href >

$("li.blocks-gallery-item figure a").fancybox({
  /* wp block version */
});

$('.fancybox').fancybox({
  /* fancybox default standard */
});