Tell SearchWP to index un-hyphenated versions of hyphenated tokens as well as the hyphenated tokens

searchwp-customizations.php

<?php

// Index non-hyphenated versions of hyphenated strings.
add_filter( 'searchwp\tokens\string', function( $string ) {
	if ( ! did_action( 'searchwp\indexer\batch' ) ) {
		return $string;
	}

	preg_match_all( '/(?=\S*[\-\_])([[:alnum:]\-\_]+)/ius', $string, $hyphenated );

	if ( is_array( $hyphenated[0] ) && ! empty( $hyphenated[0] ) ) {
		$string = $string . ' ' . implode( ' ', array_map( function( $token ) {
			return str_replace( [ '-', '_' ], '', $token );
		}, $hyphenated[0] ) );
	}

	return $string;
} );