Check out an MVC framework GitHub - rotexsoft/slim-skeleton-mvc-app: This is a template web-application (powered by SlimPHP), that can be extended to build more complex web applications. I built on top of Slim 4. I started it out on Slim 3 back in 2015 & have continued to actively maintain and enhance it since then.
There is a demo web app built using the framework here: GitHub - rotexsoft/movie-catalog-web-app: Sample app built using the SlimPHP 3 Skeleton MVC App (https://github.com/rotexsoft/slim3-skeleton-mvc-app)