Trimming Manual Excerpt

Yes, we can add a condition to make it only work for the podcast:

add_filter( 'get_the_excerpt', function( $excerpt, $post ) {
    if ( ! is_single() && get_post_type( $post ) === 'podcast' ) {
        $excerpt_length = 20;
        $excerpt_more   = apply_filters( 'excerpt_more', ' ' . '→' );
        $excerpt        = wp_trim_words( $excerpt, $excerpt_length, $excerpt_more );
    }
    return $excerpt;
}, 99, 2 );

Glad to hear that 🙂