Laravel insert multiple row in pivot table for one relational id for clone fields

Question

I have two relational tables with pivot routes, stations, and route_station. The routes table contains the route number for the metro, and the stations contains all the stations.

The pivot table multiple routes and multiple stations for each route. So not sure how to consider it. Either many-to-many or one-to-many?

HTML Form

The HTML form on the Route contains clonable fields that need to insert into the pivot table. See below.

Station
Next Station
Distance
Duration

The Question

So my question is how to insert clonable fields data (in the above list) so that insert row in the pivot table for each cloned field?

Also how I can update so it updates the exact record in the pivot table and if the clone field is removed then the record from the pivot table also removes?

Route Schema

Schema::create(
    'routes',
    function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->smallInteger('number')->unsigned()->unique();
        $table->string('code')->unique();
        $table->timestamps();

        $table->unique(['number', 'code'], 'routes_unique_columns');
    }
);

Station Schema

Schema::create(
    'stations',
    function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->string('name')->index()->unique();
        $table->string('code')->index()->unique();
        $table->text('info');
        $table->string('photo')->nullable();
        $table->timestamps();
    }
);

Route Station (Pivot) Schema

Schema::create(
    'route_station',
    function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->bigInteger('route_id')->unsigned();
        $table->bigInteger('station_id')->unsigned();
        $table->bigInteger('next_station_id')->unsigned();
        $table->integer('station_order');
        $table->float('distance');
        $table->integer('duration');
        $table->timestamps();

        $table->unique(['route_id', 'station_id'], 'route_station_unique');

        $table->foreign('route_id')
              ->references('id')
              ->on('routes')
              ->onDelete('restrict');

        $table->foreign('station_id')
              ->references('id')
              ->on('stations')
              ->onDelete('restrict');

        $table->foreign('next_station_id')
              ->references('id')
              ->on('stations')
              ->onDelete('restrict');
    }
);

Route Create/Update Form

Update

I have tried below but not working. Giving Array to String conversion error. This is because, I believe the attach and sync is inserting only one record, while the request fields is an array.

So how can I insert a record for each item of an array?

$route = Route::create([
    'number' => $request->number,
    'code'   => strtoupper($request->code),
]);

$route->stations()->sync($route, [
    'next_station_id' => $request->next_station_id,
    'distance'        => $request->distance,
    'duration'        => $request->duration,
    'station_order'   => $request->station_order,
]);