Hi Mindsugar,
Why? Becuase you set col-6 + col-sm-6 + col-md-6 for logo column.
Please read on Bootstrap 5 documenation what is and how works Grid then you would know.
It's a simple math! Without it we all lost. Summary of columns must be 12.
If logo column and menu has 50% of width - there is NO space for all menu items to display on one row when you reduce size of screen, using popular resolutions 1280px, 1440px etc.
How to fix it? Easy, reduce column size for logo and increase size for Menu column. From Template Options > Layout > Header > Columns Options > Grid > Desktop (larger/smaller).
https://www.joomshaper.com/documentation/helix-framework/layout-builder