Hi Paul,
You do need to install the driver after any reset, you can use the ".uninstall" to uninstall the driver. ".INSTALL" and ".UNINSTALL" are standard NextOS utilities to install/uninstall drivers, but the drivers are not permanently installed like they would be on other operating systems.
There are no special requirements for the installation of the driver as long as it installs successfully.
As for the video mode, as long as your Next is joined to the wifi and you are communicating successfully with the wifi module there should not be anything special that needs to be done.
Having said that, there have been some printers that just did not seem to work, I track the reports on the wiki (Home · taylorza/zxn-wifiprn Wiki (github.com)).
Did you try using the WindowsPrinterServer, I wrote that to support printers that are not connected to the wifi, but it will work for wifi printers as well. Testing with that might give us more information. I would be very eager to get to the route of this issue because other than one Canon printer I have not had any reports of the driver not working.
Other things you can check, make sure your printer has port 9100 enabled. This is the port used by the driver to connect to the printer, most home printers do not block this port, but some higher end printers might have raw printing disabled.
Best Regards,
Chris