Based on all the monitoring I've ever seen, the stats for Varnish would be the requests into Varnish.

If you wanted actual requests into the app servers you would look at those stats, and from that site, it's like ~5k req/s.

https://grafana.wikimedia.org/d/RIA1lzDZk/application-server...

I'm not sure why you think 100k req/s is low for Wikipedia