jquery loaded async and ready function not working

Question

In order to optimize the load of my document, I use to load jquery async like that

Answer 1

jQuery, and all components that depend on jQuery (including Bootstrap), depend on hooking the DOMContentLoaded event to set up events.

This means jQuery (and anything that uses $(function() {...})) must be downloaded before DOMContentLoaded fires, or it never hooks up its events.

In turn, that means