I’ll echo what others have said here: Craft CMS. It has excellent content modelling features and an editing experience that keeps clients happy. It’s PHP, which

I’ll echo what others have said here: Craft CMS. It has excellent content modelling features and an editing experience that keeps clients happy. It’s PHP, which makes it easy to host, but developing for it doesn’t feel like going 15 years into the past like WordPress or Drupal. It also has a great plug-in ecosystem. I also recommend Wagtail CMS, which is Python and built on top of Django. It’s slightly trickier to host, and doesn't have the ecosystem, but also has robust content modelling. It might be better if you’re building something truly unique, and don’t mind doing more work in-house.