Flow Limitation due to obesity

My question is does obesity and sleeping on my back the cause of extreme flow limitations? Thanks for any positive help here.

Obesity and back-sleeping can both produce obstructive apneas and hypopneas, so I imagine they can contribute to flow limitations as well. But I don't know this for sure.

It's possible for FLs to be caused by nasal congestion, but when congestion isn't an issue, they're usually caused by relaxation of the tissues lining the pharynx. My guess would be that if obesity and back-sleeping are constricting the airway, even a tiny amount of relaxation of those tissues will create significant FL.

Are you able to use expiratory pressure relief (or pressure support or "flex") to help with the FLs?