I'd love to have them support Postgres (they dropped support because of not enough developers working on it), but giving it the thumbs down for those reasons seems silly. You either self-host in which case you stuff that on its own docker instance and forget about it, or you use their hosted plan in which case why do you care what software/db engine they run?

One lightweight solution I've found great for blogs is Pelican with m.css, it's really nice and could be served even from a toaster.

Pelican? Is that a cms?

It's a static site generator: https://blog.getpelican.com

Combined with git and some webhook to regenerate on change, I think it's better than most CMSs. It's fast, nice-looking (assuming you use a theme, like m.css), secure, doesn't take much storage, really simple, nearly bug-free etc.