Do you have anyone IRL who can review your application? Red flags I can think of are:
- bad LOR
- bad ECs (which you seem to realize you might have?)
- poorly written PS, activities
For sure you could improve interview skills but your application:interview ratio is not very good. Without knowing what your ECs are, it's hard to say if it's worth waiting. If they were actually okay, maybe improve the writing and make sure your LORs are good and apply this year. If ECs are the weak point, you'll want to wait.