Maybe the 3d printed one would work better? It won't be able to be chewed, the only thing is if it may be pried off easily. Maybe a strap can be strapped around the door panel to secure it, but looking at the door panel, doesn't seem like there is a easy way to wrap around.
As for partitions, Model 3 is rarely outfitted with partitions even in police duty (probably due to limited space), but there are a couple departments that have Model Ys that have such partitions. For example Eden Prairie:
This article lists a bunch of cities that have outfitted Model Y:
Tesla Model Y joins Fremont Police Department after successful Model S pilot program [Update]
Logan also did:
Logan Police Department unveils Tesla Model Y cruiser
Maybe you can find one nearby and reach out and see if you can get the vendor that outfitted the partition and see if they can do Model 3 also.
The Fremont one actually had a BOM and that was outfitted by Priority1, but they are in Belmont in California.
https://www.fremontpolice.gov/home/showpublisheddocument/630/637775763158900000
Another idea is to create a window switch kill switch. It would require taking out the door panel and modifying the harness of the window switch. You can find used Model 3 switches on eBay to use to modify if you want to keep a factory switch just in case. Basically involves wiring an inline switch that switches off the window switch, and you can hide that kill switch somewhere. You would need to find somewhere for the new switch to exit (may need to drill hole in door panel, maybe hide in door pocket or bottom of door panel, someplace dog can't possibly toggle). For the driver side you may want a DPST (double pole single throw) switch so that a single switch switches off both driver and passenger windows, although if there is a power wire in the harness that powers the whole switch, you might be able to use a single switch that shuts off all the buttons. You would need to be pretty good with electrical if you do this mod however (or find someone that is), as it requires testing the wire harness to find which wire does what and properly connecting everything safely.