Hello Goodgrief,
I'm sorry to hear about the events that have occurred in your life. I've experienced a lot of suffering from this condition.
This topic of benzodiazepine use hits home to heart for me. I have been on 1 mg lorazepam three times a day since my initial concussion that caused PCS back in 10/2014. I was already taking the medication prior the incident and was never instructed to discontinue so I have been taking it since. I have had ambitions to try and taper off of it since I haven't made much progress in a while. Unfortunately, life stresses and other factors have deemed that impossible. I know that withdrawing now would be a torturous process as my brain is physically dependent on the medication.
I know you cited some studies about benzo use and TBI recovery. clearly it is not a good option but in your case I would be hesitant to think that any reduction in your recovery from now on will be due to that.
You and I both need to learn how to take breaks and relieve stress along with getting good sleep. It takes a lot of discipline but consider taking a 10 minute rest every hour or 30 minute rest every two hours and see how it helps. I've noticed a difference when I do that.
Lastly I will link an article which tends to be a little more neutral about benzodiazepine use for sleeping.
https://www.hindawi.com/journals/emi/2012/637171/
Hang in there, it will get better if you take the right approach.
Dan