UPDATE: I added a 3rd option which allows for the installation of a 60mm fan.  This is placed directly over the stepper drivers as I was still having a problem with them overheating.  The fan is attached using M3 heatset inserts and plugs into the anemic stepper fan port. 

I had an issue where the my AD5X was layer shifting during prints.  After going back and forth with tech support, I learned that the stepper driver fan port on the control board had died, therefore the stepper driver fan was not cooling the driver's leading them to overheat and skip steps.  After getting a new control board from FlashForge, I realized that there is no vent hole for the stepper driver fan to take in fresh air.

I recreated the back panel with 2 options.  The version I'm using has 0 top and bottom layers and a 35 percent gyroid infill to create a dust filter.  I also made a hexagon version if you want to really up your airflow game.

I have included the STL and STEP files.  The back panel is not perfect but it is really close.  I also printed this in one piece on my 350 Voron 2.4, so if you don't have a printer that big you'll have to split it up.

I printed this in PLA.  I have built entire printers out of a PLA frame so I assume it'll be just fine.