Exactly. I don't know if they've gotten better, but I worked on a headless Contentful + Gatsby site (because the previous developers got sucked into JAMstack hype) and it was a comedic catastrophe.

It required constant developer oversight, even when only publishing one or two articles a week. Things broke all the time. Builds broke constantly. Things went wrong left right and center.

Don't do it. Give them a Wordpress site.