Use of jquerry, bootstrap5, semantic HTML, CSS.

Hello, I've been struggling doing this challange for 2 days. I want your review especially for some aspects:

-How can I improve my positioning technique, because I feel that I'm not doing it in a proper or most optimal way?

-What you think about my Jquerry code and it's syntax?

-Do you have any tips for CSS styling based on my not optimal CSS style?

-What about my Mobile media querry integration?

-Is there another easier way for error handling in js/jquerry?

As much as possible sensible criticizm appreciated :> Thanks anyone who comment in advance.