[need help] How to Use SEO strategy to Promote Our New Project (a flip clock app)

Hey, indie hackers, I really need some help to promote our newly-launched project , a flip clock app. My boss don't have enough budget to place ads. So our major promotion method is SEO. However, I get confused.

Before I also promoted some our products using SEO tips. These products have very clear usage scenarios and are highly practical. I was able to target our audience quickly through their features. And I can create interesting content around these products and build good backlinks easily. But this time, the product is a flip clock app, I don't know how to promote it via SEO.

Its major function is time display. Users can install it on their iPads or iPhones, and turn their devices into a full-screen digital clock. Yes, I can say that it is a tool to keep us focused. Or I can say it is a good gadget to decorate your workspace and study room. But do users really need it? I mean, it is not a Must-have tool. I found it is difficult to create interesting content to capture the user's attention. In addition, when I do outreach for backlink building, I couldn't find an angle that would get the admins interested in this product.

Brief intro of my app: Flip Clocker
Flip clocker is a smart digital clock available on Mac, iOS, and iPad! It can turn your phone and Mac into a full-screen digital clock and display time in a fun way. It offers multiple themes and backgrounds to display time and date. You can use it as a simple screensaver to decorate your workspace or use it as a productive tool to make yourself focused.

Project website: http://flipclocker.com/

For such a product, how should I promote it using SEO? I feel so frustrated now. Really need some advice from you. And I am very sorry for asking such a possibly stupid question.