Tell SearchWP to index term meta

functions.php

<?php

function my_searchwp_indexer_taxonomy_term( $term, $context ) {
	
	$taxonomy = 'my_taxonomy';
	$term_meta_key = 'my_term_meta_key';
	
	if ( $taxonomy !== $context['taxonomy'] ) {
		return $term;
	}

	$term_meta = get_term_meta( $context['term']->term_id, $term_meta_key );

	$term .= ' ' . implode( ' ', $term_meta );

	return trim( $term );
}

add_filter( 'searchwp_indexer_taxonomy_term', 'my_searchwp_indexer_taxonomy_term', 10, 2 );