Your story sounds identicle to mine. Even our sizes are close. Only difference is age. I'm 62. I quit smoking 11 years ago,and have been gaining ever since. My workout is also very similar to yours, done most days of the week.
I have no advise, as I too have tried & tried. Just thought i'd let ya know there are others in the same battle. So [if] you find a secret please share!?
One thought..some say stick to your routine, but up the weight lifted? It yields more intensity, more burn? I tried it for six months,..it didn't help,and started hurting my joints, so I backed off.