Improving PHP MVC code for personal website
If you want to learn best practices in MVC, I would suggest you to have Slim framework. If you don't want to use an existing framework and develop your own, still, I would recommend to install it on your local and understand how they are doing. Laravel is another best, but it would be overkill for a personal site. 

Check their Routing example. You are almost close in your routing, but if you want to know the best practices, they have it: http://www.slimframework.com/docs/v4/objects/routing.html

In your example, I would include init.php and routes.php inside of index.php to keep it clean and declarative. Your init may eventually grow and it would become clumsy.