I have completed my move from Joomla. For years I developed websites in Joomla, but when I quit developing websites I found my remaining personal websites did not need a CMS as complex as Joomla. Not that I dislike Joomla, it is a great CMS. But I don't need a One ton truck anymore.
So I started looking for a smaller simpler flat CMS. I came across a small CMS called Yellow from Sweden. I have no idea how big the user base is but it met my requirements: simple to setup, and simple to use.
I tried Grav but did not like it. That is not to say Grav is bad in fact it is one of the most highly rated and popular flat CMSs. My philosophy is that in a CMS the content, the plugins, and the templates should be independent. One should not be dependent on the other. That is not the case with Grav. The way the templates work content can often be template dependent. If you never change templates that is never an issue but if you have an existing Grav site and change templates it is quite possible and very probable that your site would not display and error out. You would have to edit every article to make it compatible with the new template before the site would be functional. I believe there is a way to bootstrap templates so your site can function if you change templates but that seems like a lot of extra work.