Does KOLIDE_FILESYSTEM_RESULT_LOG_FILE still working? My query packs doesn't log anything on filesystem

It should, assuming you configure

filesystem

as the logger plugin to use (https://github.com/fleetdm/fleet/blob/master/docs/2-Deployment/2-Configuration.md#osquery_status_log_plugin). See also https://github.com/fleetdm/fleet/blob/master/docs/1-Using-Fleet/FAQ.md#where-are-my-query-results

Yep