I use fredo6 joint push pull plugin to do push pull on selected surface and do it normally but unfortunately the surface didn’t change yet, it remains on the same position, or maybe i did it wrong??
I think I know what you want, but I am not sure. Maybe show the ‘before’ image as well?
As an idea, maybe it would be easier to just redo the geometry using Upright Extruder?
JointPushPull has a ‘thicken’ option. Have you tried that?