Welcome to the site!
I have found that many directors like to work in a collaborative environment -- everyone's ideas are fair. I enjoy that aspect of creativity within the production. Also, I find that once the show is running, there is often a bit of ebb and floe in the calling of a show. If a particular joke lands really well on the audience, I may hold the doorbell sound cue that takes us into the next scene. It's a matter of milliseconds, but your contribution as the stage manager is to support the production towards its best version.
Another creative responsibility of the stage manager is problem solving. When things go awry, the SM has to think on their feet and solve it in the best way possible. Do you send a cast member onstage to clear the prop that fell off of the rolling wagon during the last scene change? Do you wait until the next blackout? Can you even wait that long or is a line of chorus girls about to head right through that space in tap shoes at breakneck speed? Do you have crew members in costume? Do you even have an extra cast member to take care of it? All of these questions need to be answered (and quickly). There's a lot of creativity involved.
Finally, if those kinds of creativity aren't enough for you, find an outlet that satisfies you. Draw, paint, play music, write, dance. Do something in your spare time that will fill your creativity quota.
Personally, I very much enjoy the 'business' aspect of stage managing. I call it the mathematical side of theatre. But I also need a creative outlet (and it helps to have a place to let off steam away from work). I play piano as a stress reliever. I also keep a coloring book and a box of colored pencils around when I'm working. It's mindless enough and creative enough that it becomes a great way to wind down after a long day of tech.