I'm sorry that you're experiencing akathisia

When I have had it, I found pacing helpful. I will literally pace for hours until I am finally able to be still, or I can't physically walk anymore. I've never tried benztropine, but I have been given benzos (diazepam) before for it. Technically they did help a bit, but I very quickly became tolerant to them and the dose had to be increased often, which is very problematic with benzos, so I'm not sure that I'd necessarily recommend that option unless you were absolutely desperate.

I think that you should get in touch with your pdoc and see how quickly the benztropine is supposed to help or, if it should've helped by now, if you can increase the dose or alter the doses of the haloperidol/quetiapine. Unfortunately taking 2 APs means a higher chance of side effects.

I hope that you find something to help as akathisia can be really awful

*Willow*