That sums it up pretty well.
The great irony here is that those thin, stateless web servers that are the only things to easily autoscale are pretty much guaranteed to never be your performance bottleneck, unless you're doing something really strange.
all you have to do is run Wordpress with Woocommerce, multiple additional plugins and an overloaded theme with visual builder/editor that needs 512 megs of RAM and 500ms to display a contact form[0]. Some themes can be amazingly CPU intensive.
[0]and 900+ queries, but since most of them are simple selects any cache like redis or memcached removes their performance impact.