There is also #Drupal ( https://www.drupal.org/ ) and its fork #BackdropCMS ( https://backdropcms.org/ ), but Drupal is really just a set of frameworks for building your own CMS. It gets really complex quickly. If you’re going to build dozens of sites with it, then it is worth learning all the pieces and how to fit them together with your own customizations. If you’re building one or two sites, look elsewhere.
We have a new project for which we are using Alfresco. I think it's more of a SharePoint competitor than any of the ones you mention, but I guess it just depends on what you want.
@musicman I ran #Alfresco at home over a decade ago. It was way more than I needed (and I don't think they were competing with #SharePoint yet ). A HDD crash while I was out of state ended that.