Unless you have a good solution in place that abstracts away the CMS, and triggers automatic (near-instant) redeploys, that's usually not a good idea.
Your marketing team(/person) will have to do many dozen changes a day on your landing pages, and you don't want them having to wait for changes to appear on the website.
A base WP setup that is managed via version-control + WPs normal live CMS is still one of the best CMSs out there IMHO.
Maybe "landing page" wasn't the correct term here.
> I would really like to see examples of this.
I almost struggle to come up with a non-example for this for any profitable tech company.
Look at the sitemap of e.g. Solarwinds[0] or Hashicorp[1]. Both have thousands of sub-pages with different marketing copy as content to capture as much organic traffic as possible and to convert paid traffic as good as possible. That marketing copy doesn't write and update itself (or at least it hasn't until recently).
If you look on most job boards you will also find many positions that contain "SEO" in their title. While some of them are more rosy "SEO management" positions, if you squint a little bit, you'll see that in practice those people spend a good chunk of their day in their CMS (likely WP) to create new pages and updating existing pages based on conversion tracking data. That also usually doesn't have a lot to do with "incompetence", as that process is rarely something where you can one-shot the right solution. More realistically you'll just have to try out a lot and see what sticks (both with search engines and people).
You probably need a headless CMS of some kind so the client can manage it. I've used decap/Netlify CMS, and it's fine, but it's clearly not anyone's priority anymore.
Your marketing team(/person) will have to do many dozen changes a day on your landing pages, and you don't want them having to wait for changes to appear on the website.
A base WP setup that is managed via version-control + WPs normal live CMS is still one of the best CMSs out there IMHO.