I had to scale a high profile Wordpress site during the pandemic. It got huge spikes daily during a press conference. It got 150k hits per second.

Apart from moving it from windows to Linux, I put it in front of varnish and spent a few hours tweaking the config to make sure everything still worked. It was my first time using varnish so it took longer.

It performed flawlessly for years.

Varnish was a real workhorse.