Help on z axis screw

I need help to Choose how to move my z axis.

Previously there was an hydraulic piston, now gone.

I have a nema34 stepper ready to couple, but I need to build the support for the screw. Here the problem: the space is minimum for the screw.
The gap between the moving plate is just 19mm.
Therefore I’m worried how to fit the “brass nut”.

I’m thinking at other solution, like “pushing and pulling” the plate having the 2 screw extremity moving, and the centre nut steady.

I’m open to other suggestion, please let me know your thought guys, It’s the last part of the build.

Check the pic for more

Attachment 26748

Attachment 26749

Attachment 26750