To the google tops with landing page only

Hi guys! I'm desperate. I don't know how to make Google to index my site better.
Is there any formula for sites that have only landing page.
Here is mine - https://todox.app/
As you can see here is only landing page, and then only your private ToDo list with no interesting information for G bots.
So is it possible to improve SEO somehow. And in what extent can it affect position in search?
Thank you!