Using filters to change href of nav menu page link

I’m trying to find a way to change the href of a nav menu page link from the parent theme’s default, which goes to its relative page, to another url. For example, I have a menu link “Our Philosophy” that links to the “Our Philosophy” page, but desire for it to go to timecube.com (rip).

It seems perhaps using a filter (nav_menu_link_attributes?) might be a simple way to achieve this. However, I’ve been unable to wrap my head around using filters to get this working.

I would think I’d need something like:

function change_nav_url( $atts, $item ) {
    // modify $item href?
}
add_filter ( 'nav_menu_link_attributes', 'change_nav_url');

My initial thought would be I would need to call this function somewhere–with apply_filters() maybe–and would need to get $atts and $item manually from somewhere and pass them into it. But that creates the problem–how do I get them, and from what (a menu object?). And thinking about it, if I do have to retrieve them manually, I don’t really see the point of using a filter v. a plain function, so maybe I have to put it into the plugin folder and it’ll automatically give me access to $atts or something? (That didn’t work). Either way, I’m clearly not understanding something.

I appreciate any help bringing light to my newb ignorance.

You are on right track, with few minor kinks.

1. You need to modify $atts and return it. Any arguments after the first one are provided for information and should not be changed.
2. You need to tell add_filter() that you expect more than one argument.

The example with some debug code would be along the lines of:

add_filter( 'nav_menu_link_attributes', function ( $atts, $item, $args, $depth ) {

    var_dump( $atts, $item ); // a lot of stuff we can use

    var_dump( $atts['href'] ); // string(36) "http://dev.rarst.net/our-philosophy/"

    var_dump( get_the_title( $item->object_id ) ); // string(14) "Our Philosophy", note $item itself is NOT a page

    if ( get_the_title( $item->object_id ) === 'Our Philosophy' ) { // for example

        $atts['href'] = 'https://example.com/';
    }

    return $atts;
}, 10, 4 ); // 4 so we get all arguments