Auto-Scheduler

Auto-Scheduler does what Motion used to do, and not much else. There's no "AI", not teams, little project management. It's focused on solo users that are just trying to lessen their mental load a little by not having to worry about what to do when, and it's priced accordingly. Don't pay for services and features you don't want or need.
Auto-scheduler takes your to-do list, a duration and priority for each task and then writes them into your Google calendar as events. It plans around your existing schedule, never touching the events you created manually. That's basically it, but the web app is full of options if you want to customize it for yourself. There's a 31-day free trial. You get 100% of the features during that time.