How to create video sitemap on the fly ?

my site has 40k ++ posts, manual bulk editing takes a long time and also not all videos are hosted on youtube.

I’m using this code, but sitemap gets no limit. how to limit the video-sitemap so that it will make their pages 1,2,3 .. following sitemap settings links per sitemap (currently 1000 links per sitemap)?

/* Filter to add links in the new Sitemap.*/
add_action( 'rank_math/sitemap/video_content', function() {
	$site_title = get_bloginfo('title');
	$site_url = get_bloginfo('url');
	$postsForSitemap = get_posts( array(
        'posts_per_page' => -1, # total 40k++ post
        'orderby'     => 'modified',
        'post_type'   => array( 'post' ),
        'order'       => 'DESC'
    ) );
	if ( str_replace( '+', '', get_option( 'gmt_offset' ) ) < 10 ) {
        $tempo = '+0' . str_replace( '+', '', get_option( 'gmt_offset' ) );
    } else {
        $tempo = get_option( 'gmt_offset' );
    }
    if( strlen( $tempo ) == 3 ) { $tempo = $tempo . ':00'; }
	$index = '';
	foreach( $postsForSitemap as $post ) {
        setup_postdata( $post );
	$postdate = explode( " ", $post->post_modified );
	$get_title = get_the_title($post);
	$get_url = get_permalink($post);
	$urlgambar = get_field('series_thumbnail_ex', $post);
	$get_series = get_field('series_seri', $post);
		if( !empty( $urlgambar) ) {
			$getgambar = $urlgambar;
		} else {
			$thumb_id = get_post_thumbnail_id(); $thumb_url = wp_get_attachment_image_src($thumb_id,'', true);
			$getgambar = $thumb_url[0];
		};
	$get_video_duration = get_post_meta( $post->ID, 'series_videoembed_duration', true );
	$index .= '
	<url>
		<loc>'.$get_url.'</loc>
		<video:video>
			<video:title><![CDATA[Nonton Anime '.$get_title.' Sub Indo  - '.$site_title.']]></video:title>
			<video:publication_date>' . $postdate[0] . 'T' . $postdate[1] . $tempo . '</video:publication_date>
			<video:description><![CDATA[Nonton Anime '.$get_title.' Sub Indo. download streaming resolusi tinggi 720p, 480p, 360p lengkap Full HD Batch Mp4 dan Mkv online gratis]]></video:description>
			<video:player_loc allow_embed="yes">'.get_embed_url($post->ID).'</video:player_loc>
			<video:category><![CDATA['.get_the_title($get_series).']]></video:category>
			<video:thumbnail_loc>'.$getgambar.'</video:thumbnail_loc>
			<video:duration>'.RankMath\Helper::duration_to_seconds($get_video_duration).'</video:duration>
		</video:video>
	</url>';
	};
	return $index;
});