Rebuild the navigation logic of the website on WordPress without data loss.

rewrite the logic of the website navigation.
Preservation of functionality
It is essential to preserve:
all existing content;
the search function;
filters;
internal links;
that is, all existing features.

Result of the work
In the end, the client receives:
updated/corrected navigation logic;
a stable working website without data loss;
optimized plugins;
a backup of the website;
a brief description of the changes.