Conditional tag only for front of custom post type

there is an is_post_type_archive() function https://developer.wordpress.org/reference/functions/is_post_type_archive/ that will tell you if you are on the https://example.com/projects/ page.

In your case you would need to use it like this

is_post_type_archive( "projects" );

since “projects” is your custom post type name.