For static sites Forestry.io is good. The editor experience is great and you can do clever stuff with front matter - including adding a component based layout builder.

https://forestry.io/blog/blocks-give-your-editors-the-power-...

Co-creator here. We just launched some starters if you want to kick the tires. https://forestry.io/starters/

The UI for these starters doesn't show off advanced stuff, but click on "Front Matter" and add complex fields/groups/blocks to get a feel for the UI.

Craft or Directus probably if I had more time.

My requirements at the time were:

- Can be integrated in a Vue static site generator

- Has a free plan (single user)

- Could be hosted for free at least during development

- Could have relations ("Post" can have a "Category" field that list its content as options)

- Has a admin UI that a non-developer could figure out

Craft CMS