> Coding a basic vanilla multi-page application (MPA) saves time in development (goodbye babel/postcss/SSR config) and builds are fast (this site builds in less than 1.2 seconds).
I'd hope that builds would be on the order of a small pile of milliseconds! (or zero: a site like that could just be handcoded, really).
> I'm only using these 2 lines of Javascript to add the current year in the footer copyright tag
This could also be eliminated. At least in the US, there is no legal reason to add a copyright notice at all, and you certainly don't have to add a year. Those requirements were removed years ago.
But, if all you want is the year, why not do that server-side? Or bake it into the html and set up a bit of automation to replace the year with a new one every Jan 1.