What's wrong with my dropdown?

Question

css

There is a site Tyk after transferring to bootstrap 5 broke navbar returned the visual component but stopped working dropdown if the site is open in the mobile version, but if you reload the site in normal size and change the page size, everything works but nothing works in the opposite direction. What is wrong and where am I stupid
I would like to add something I have problems with the navigation bar and not with the search bar on the site

Answer 1

Bootstrap 5 has moved to flex.
getbootstrap.com/docs/5.0/examples/
Look for a navbar here and just shove it to you