You can get 4" couplers with male and female ends. Cut the female end so crimped male end is usable. 2-3 screws where permanent and if joint is tight, no taping is necessary. Outside the wall, one screw should be fine. I don't use band clamp because dryer outlet is recessed and never was able to make the clamp tight. I would not fill the spray foam. It's not as fireproof as claimed. Fiberglass insulation. Remove the vapor paper, grab a handful of fiber and crush them into any gap. Foam may be good for air sealing in the stud bay but not around the duct.