Would a sliding genioplasty and rhinoplasty help improve facial image? Any other recommendations for a flat face? (Photo)

The assessment you’re asking for is not simple or straightforward.
The fundamental issues are deeper than the mentalis of your mandible or the shape of your nose.
I suggest having consultations with oral surgeons to get a thorough assessment of cranial facial structure.
Regardless of what procedure you choose it is helpful to have a clear understanding of the primary issue.
Facial aesthetics are generally based on bone structure.
Each person has a unique appearance and altering that is sometimes appropriate and this depends significantly on the desire of the individual.
In the end the decision comes down to what you’re trying to achieve and what you’re willing to go through.
The process should always start by having a quality assessment with a clear understanding of what the primary problem is.
If the maxilla lacks sufficient projection and the problem isn’t fixed by altering the nose.
That doesn’t mean you can’t have a rhinoplasty.
It simply means that understanding the primary problem will help make the best decisions in regards to treatment options and also accept inherent limitations if choosing procedures that don’t directly relate to the primary problem.
In your case I suggest having consultations with providers who have training in craniofacial surgery whether from oral surgery background or plastic surgery background.
In the end you may opt for the procedures you have described but having an understanding of all alternatives including what would give the best results is best done before scheduling any procedure.
Good luck,
Mats Hagstrom MD