There isn't a true replacement for Wordpress because of the sheer availability of plugins it has.
But for simple sites like blogs and personal sites Grav CMS is one I've used, and it gives you a web admin panel similar to Wordpress, so the learning curve isn't too bad.
Drupal also gets mentioned a lot as a replacement.
There are also static site generators like Hugo, but those require learning a lot about the specific one you use, and are pretty complex to use, and if you need non-static content like a web form or something it can add a lot of complexity to your whole setup.
An AFK kick seems simple enough to stop most of those situations.