You can - there are ways to make certain areas of the page like the footer static throughout the site using Javascript so that updating the Javascript file updates everything in that section. I wrote a bit about it here, but my way of doing it is really basic. https://fabled.day/medium/static
I WANT TO SAY I CAN DO THIS WITH A LITTLE JS,??? MAYBE????
You can - there are ways to make certain areas of the page like the footer static throughout the site using Javascript so that updating the Javascript file updates everything in that section. I wrote a bit about it here, but my way of doing it is really basic. https://fabled.day/medium/static
Petrapixel has a tutorial too, even with these cool nesting options. https://petrapixel.neocities.org/coding/layout-base-code