It's getting a bit older. But I use Zim on Linux for Year now. It's a text editor similar to a personal WIKI. You do have options to create a Todo List with Checkbox. It support a couple of plugin too.
The only draw back: it's a desktop application.
Take a look: https://zim-wiki.org/
I usually use vim/nano directly. I don't see the need to edit file directly very often.
Following good DevOps practice, I usually push server configuration with an ansible playbook and most application are running on Docker. The number of time I need to edit config file is very minimal.
But I would understand if ansible deployment is a bit too far for your self hosted need.
Privacy and control are the main reasons why I host some of my data myself. This choice is closely linked to my values, as I'm not comfortable with the idea of entrusting my data to large companies whose only motivation is to make more money over customer satisfaction. I prefer to keep my autonomy.
However, simplicity is the main reason why I choose not to self-host certain elements. For example, I'm not yet ready to manage the self-hosting of my e-mails.