I'm from the UK, and I have never heard this expression. 🤔 Maybe it exists in some other English speaking country... I have heard of, "to have one's feet on the ground", meaning to be sensible and rational in one's thoughts and actions...

I haven't really heard it personally. I feel like it might not be common where I live or maybe in my age group

It means to be a sensible or a pragmatic person,

Hey! It means to keep yourself grounded,not to get arrogant 🤝🏻