True. I briefly mentioned Headless CMSs but didn't really give them the time of day. I didn't want to do anything that required a server/db/CMS, but I didn't do a good job of justifying that decision.

I do think the term "tech stack" has come to be used more broadly than your definition.

It’s using tech mostly used on the frontend (React), but using it on the backend via Next.js to generates static files that you can serve with any simple host you like.

What do you mean? It is Jamstack, you only need CDN to serve it.