Performance is very bad

[official-sounding]

Describe the bug
On a post page: https://ask.metastaging.net/2504/does-this-work

• On a 4G connection (via lighthouse), the site takes over 3 seconds to get a first contentful paint (FCP)
• When simulating a "slow" device (3G connectivity, with cache turned off), it takes over 10 seconds to get a FCP

This seems to be mostly caused by font downloads & ckeditor. ckeditor is probably fixable via proper use of the async and defer attributes on it's script tags. font downloads probably require a more comprehensive fix.

To Reproduce
https://pagespeed.web.dev/analysis/https-ask-metastaging-net-2504-does-this-work/qc0djv0p2f?form_factor=mobile
Or use the "Lighthouse" tab in Chrome Devtools
Or use the "Throttling" dropdown in the "Network" tab in Chrome Devtools

Expected behavior
I would expect a mostly text-oriented site like Metafilter to load fast, even on slow connections. It's worth serious consideration if Metafilter needs to load 3 different custom fonts to render, or if system fonts/a single custom font would be preferable.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: Windows 11
• Browser Chrome (latest)

Additional context
Kirk's stated goal was to focus on performance "at the end". This feels very backwards to me - if you start out with a fast site, it's easier to understand specifically what is making a site slow (because adding that thing to the loading chain will make your site slow). You can then make small, specific fixes at that time to make things fast.

If you wait until the end, you have multiple, possibly interlocking gremlins to chase down, potentially compromise your otherwise tested features and may need to perform significant rework or compromise functionality to get to acceptable performance.