I used to ask for feedback like this:
Illustration of two stick figures, both smiling. Person 1, the employee, has short curly hair, and person 2, the manager, doesn’t have hair.

person 1 (speech bubble): dо you have any feedback for me?
person 2 (speech bubble): not right now!
person 1 (thought bubble): is there something they’re not telling me?
person 2 (thought bubble): what specifically does she want feed back on?

I’ve learned that I get WAY BETTER answers if I ask more specific questions! - what do you think of this design? - did I prioritize these things well? - should I be doing more or less of X? - do you have any concerns about PROJECT? - was that email clear?

Bonus: asking specific questions forces me to actually think about which areas I might want to focus on.