Why annual? There are many deciduous ground covers that you won't have to plant year after year. Evergreen ones, too.

There are responses to "foe lawn" in this forum that you might find helpful, including a link to an article about clover.

I've used a mix called "Fleur de Lawn"

Low maintenance. In fact there are places I've not mowed it at all without a wilderness showing up.

Here is a link that might be useful: Low maintenance seed mixes