Very lovely work! I dont think it is too bland. It's got it's own thing going on, very clean and good shapes.
As for suggestions, I think the one thing that sticks out to me the most is the gradient. I think it is the biggest contributor to why you think it is bland. Maybe making it be a more interesting change of colours rather than just a straight line gradient would help a lot.
Some other ways how you could possibly improve the boring feel is adding more contrast here and there. For example some rim light around the character to better make it pop. Some little wavy things in the water reflecting light. Darker colours towards the bottom of the image, so the eye focuses more on the middle. As well as maybe bigger foreground elements. You got the right idea there already, with adding that grass, but maybe making it bigger would help.
Anyway, here I very quickly whipped up some edit to illustrate my points. Hope it helps! In any case, you're doing great!
