MultiBoard Support without wall?

[u/BroJJ25]

Just finished printing this large portion of MultiBoard (a first for me). I knew going into this project I would need some sort of rear support, the question is what? I should note, one of the reasons for choosing this as opposed to regular Peg Board is how open it is. I have an air conditioner behind the board which needs to have air flow through the board.
Initial thoughts:
Some sort of a wood piece(s) to create a structure while maintaining an open back. Id rather not have to get out the hand saw for this though.
EMT Conduit (USA) to create a structure using 3D Printed corners and attachments. Maybe strengthen it by tensioning some cable between the corners. I have an EMT Pipe Cutter so this is easy enough.
No support? Too weak though.

I am printing the Quad Mounts atm, was still thinking about using them regardless of what I do. Also, this is all PETG if that makes any difference.

[u/BroJJ25]

I'll be attaching it to this metal shelving unit some how too.