With such a high number of requests, it is not enough to just adjust the configuration of the LSWS, because the problem is not the web server, but lower-level modules such as PHP and MySQL, because this creates the greatest load. The web server is only the provider of the requested data. The web server can answer as many simultaneous connections as PHP and MySQL are not fast enough to process the requests.
To significantly reduce the load, use LScache whenever possible. If this isn't enough, LiteSpeed WebADC has everything you need to serve an almost unlimited number of requests without delay.