Unfortunately both the P900 and Z3200 are extremely buggy drivers.  Since RR Aurora White 300 is not a standard Epson media type, I assume you added custom media types using the Epson tool?  If Qimage and the driver don't align on media type it means the driver has a corrupted media type table and is not reporting the proper media types to Windows.  This can sometimes happen when you use the Epson media tool to create new media types and the tool does not properly update the media types (and indices) in Windows or crosslinks some media types so that multiple media types have the same numeric index.  In a case like this (where only the driver can see the correct custom types), you have to select the media type in the driver.  Don't try to change media type in Qimage if you are having this problem because the driver has given Qimage a bad media table (index).

As far as I know, this is only an issue with the HP Z series printers and Epson P900.

Regards,
Mike

Color management is turned off in the driver so no profile will "make it to" the driver anyway: Qimage is handling that on its own.  So there is no need to worry about the profile other than making sure the profile is the correct one for the media type: in this case, the media type in the driver since the driver is not communicating media information (type and size) properly.  I didn't notice the size was incorrect too as you didn't mention that: never seen that before so the P900 driver must really be broken!  Again, in a case where there is disagreement, pick the size in the driver because the driver isn't listening to Qimage.

To put it simply: set both the media type and media size in the driver since the driver seems to have gone "off the grid" with those settings.  The driver may only be broken for media type and size on that one media type or a few media types: it may work for others, particularly for Epson standard media types.

Also, keep in mind that Qimage doesn't "force" you to do anything!  The media type, size, source, etc. on Qimage's main window are there for convenience only.  You could operate Qimage like any other program requires (PS, Lightroom, Affinity, etc.) and just open the driver via "Properties" and make all your selections there if you like.  The ones in Qimage just send the selection to the driver anyway so in the 0.1% cases where the driver may have gone deaf for those, just open the driver and do it directly.

Mike