Have a look at TasksInaBox ( https://tasksinabox.com/ ). What is nice is that besides the usual web and mobile apps, it also has a client living inside Outlook so you can create tasks from emails as they arrive in your inbox.
There's a book called "Personal Kanban" about using Kanban to organize your own work. I liked some of the principles it espoused, but ultimately found it awkward to manage returned to a more traditional set of GTD lists.
Yeah, I find myself starting new things all the time and never finishing most of them. I've used a WIP limit to try to force myself to finish or explicitly dump projects.
Considering it for myself, even if it isn't the intended use case.