SSDI will likely want to see a NeuroPsych Assessment plus your medical records. They will consider if there is other work you can do. Do you have a Vocational Rehab Agency that can do an assessment ?

Many use SSDI attorneys or agents. They get paid 25% of your back pay so there is no out of pocket.

You can always rest to get improvements. What you want to do is simple activities that do not cause a return of symptoms. In most cases, the subject has a baseline of PCS symptoms (head aches, sensitivity to sound and light, etc) and when overdoing it, will manifest a new or increasing set of symptoms (cognitive crash, mental fatigue, outbursts, etc). Managing your activities to stay at the baseline without any increases is the best way to help with recovery.