I recently replaced a brother printer with this Xerox printer. It is connected wirelessly and I downloaded the driver from Xerox to install on both my Mac running Mojave, but I am also having the issue on Catalina.
On both machines there is no option for duplex printing. I thought this was an available feature on this printer but I cannot find a way to enable it on these macs.
Below is a link with pictures of what I can see: