I have tested this several times now this section below does not display any text for empty fields

return $content . __( ‘Following details are missing’ ) . join( ‘ & ‘, $missing_details );

thats exactly my point see image https://ibb.co/HNZrFBy

Sorry for the trouble

This is my code

 add_filter( 'the_content', function ( $content ) {

	// Our donation page link.
	if ( ! is_page( 36918 ) || ! isset( $_GET['user_id'] ) || ! $_GET['nonce'] ) {
		return $content;
	}

	$user = get_user_by( 'id', absint( $_GET['user_id'] ) );

	if ( ! $user || ! wp_verify_nonce( $_GET['nonce'], 'donate-' . $user->ID ) ) {
		return $content;
	}

	$bank_name               = xprofile_get_field_data( 3217, $user->ID );
	$account_number          = xprofile_get_field_data( 3218, $user->ID );
	$account_name            = xprofile_get_field_data( 3219, $user->ID );
	$paystack_url            = xprofile_get_field_data( 3220, $user->ID );
	$crypto_currency_name    = xprofile_get_field_data( 4447, $user->ID );
	$crypto_currency_address = xprofile_get_field_data( 4446, $user->ID );

	$missing_details = array();

	// Replace field id with your one mandatory for donation. If empty return your message.
	if ( empty( $bank_name ) ) {
		$missing_details[] = __( 'Bank name has not been provided' );
	}
	if ( empty( $account_number ) ) {
		$missing_details[] = __( 'Account number has not been provided' );
	}
	if ( empty( $account_name ) ) {
		$missing_details[] = __( 'Account name has not been provided' );
	}
	if ( empty( $paystack_url ) ) {
		$missing_details[] = __( 'Paystack URL has not been provided' );
	}
	if ( empty( $crypto_currency_name ) ) {
		$missing_details[] = __( 'Cryptocurrency name has not been provided' );
	}
	if ( empty( $crypto_currency_address ) ) {
		$missing_details[] = __( 'Cryptocurrency address has not been provided' );
	}

	$render_shortcode = false;

	if ( $bank_name || $account_number || $account_name || $paystack_url || $crypto_currency_name || $crypto_currency_address ) {
		$render_shortcode = true;
	}

	if ( ! $render_shortcode ) {
		return $content . __( 'This member has not provided any payment details, the following payment details are missing: ' ) . join( ' & ', $missing_details );
	}

	ob_start();

	// Replace group_id to your group id.
	echo do_shortcode( "[bpsc-user-avatar user_id={$user->ID}]" );
	echo do_shortcode( "[bpsc-user-display-name user_id={$user->ID}]" );
	echo do_shortcode( "[bp-shortcodes-profile user_id={$user->ID} group_id=2]" );

	$shortcode_content = ob_get_clean();

	return $content . $shortcode_content;
} );