Best Open Source CMS?
Which CMS would you recommend nowadays for an experienced developer to start a new website/app with and which is flexible for customization?
I had a good experience with grav. It being file based (i.e. no db) made it very easy to understand and modify to do what I needed. The included admin dashboard makes it pretty straightforward to hand content administration to non-dev users
WordPress? Really depends on what website or app you have in mind.