The replacement they're whining about is "core web vitals" IE the metric you can view at[1]. This is what AMP should have been in the beginning and I was surprised they did something else, it made Google search unusable on mobile. [1] https://support.google.com/webmasters/answer/9205520?hl=en This means that your hand-coded-in-vim static pages will rank near the top.
There is one metric where hand-coded-in-vim pages tend to do poorly, and that's cumulative layout shift. If you have images on your page (a reasonable assumption) and just stick tags in there, you can get dinged on cumulative layout shift because the layout will shift as images get loaded. I use a somewhat hand-coded-in-vim approach, but there's some post-processing that adds width/height attributes to tags which mit…
Those are used to determine the aspect ratio, so even when resized via CSS the browser knows how much space to reserve in the layout.