quedarse sin pan y sin torta

listen to the pronunciation of quedarse sin pan y sin torta
الأسبانية - الإنجليزية
fall between two stools
To fit into neither of two categories and, hence, be neglected or fail
To attempt two roles and fail at both, when either could have been accomplished singly

As your chances of mega-success increase so do your chances of falling between two stools, and if you get it wrong, you could end up with a dog’s dinner that satisfies no one.

fail because one hesitated between two opportunities, attempt two things at once and fail at both