Just vibe code your own mini cms on top of your static site. Seriously though, I did this recently with mine and have had great results. It's not a Gutenberg WP experience, more like a decapCMS kind of thing.
That being said... if you're the sole author of your site, anything goes and yeah, you probably don't need a proper CMS. I certainly built my own share of 100-line Perl static site builders back in the day.