I bet your therapist meant for you to do activities that cause dizziness for a short time then rest. Pushing too long can cause brain overload and fatigue making things worse. Do an activity until dizziness starts. Take a break. Next time, do it just a bit longer then take a break. For me, the break can be just a minute or even a few seconds to allow things to settle.

Regarding healing. A concussion is not a single event or injury. It is a process with injuries to various systems. Different symptoms will improve over different time schedules. Some will have a single symptom that seems to last long after the others have resolved.

I wonder if some of your ear symptoms may be due to pollen. It is that time of year. I rarely have a problem with pollen but this year has been bad.

Your diagnosis of vestibulo-ocular reflex dysfunction could possibly be plain post concussion nystagmus with no inner ear involvement. Were you tested for nystagmus without moving your head ?
You could have two different issues. Simple PCS nystagmus and also a vestibular dysfunction.

For some of us, mild vestibular issues have persisted for quite some time. We just learn to live with them and sometimes, we eventually realize they are gone. If I move too many directions at once, I will get momentary symptoms. If I stop and stand still for a few seconds, they go away. So, I try to get up from a chair in two movements. I lean forward, pause for a fraction of a second, then I stand up.