German visa refusal on lack of proof of ties to home country. Should we appeal for review?

I am currently living in Germany on Blue Card and receiving a handsome salary. My wife is living in Pakistan. We are a newly married couple. She has registered herself in German Consulate for the family reunion visa but the waiting time to get the appointment is more than a year.

So, we decided to apply for a short-term Schengen visa (alongside waiting for the family reunion appointment date). She applied with all the required documents but got a refusal. The reasons for refusal are "You could not prove sufficient family ties to home country" and "You could not prove sufficient economic ties to home country".

I understand the reasons as stated someone else that She should provide followings:

1. A steady job with income.
2. Family ties (kids going to school for example, spouse, etc.).
3. Property or other assets.
4. Other similar evidence.

But the problem is,

1. She does not have any job (no employment relationship).
2. She is living with my parents and she does not own any house or property (no family ties and no economic bond).
3. She has finished her last degree and she is not enrolled in any school or university.
4. She does not have any kids.
5. She never visited Europe before (no last Schengen-Visa).

In the consideration of the above points, what can she have as a proof to show family and economic ties? What can we write in the appeal to convince that she doesn't have any intension to stay in Germany for more than 90 days as we have already registered for the family reunion visa in the consulate before applying to Schengen Visa?

I believe that from my side and other documents are Okay (we provided all the documents that we can), we just need to provide any document that shows her ties to home country Pakistan. Please guide what documents can we provide. Is it a deadlock for her?