This isn't the guide for you
The Internet is full of guides on easily making your WordPress installation run fast. If you're looking to speed up your WordPress site, you should go read those, not this.

Those guides often boil down to the same old tips:

uninstall unnecessary plugins, nginx, web development, published on gemini, web, performance, wordpress

Suppose you're running an application on a Passenger + Nginx powered server and you want to add caching.

Perhaps your application has a dynamic, public endpoint but the contents don't change super-frequently or it isn't critically-important that the user always gets up-to-the-second accuracy, node, nginx, web, caching, proxy, python, ruby, passenger