@walkero
Yes, the pwg-raster bit needs a proper printer driver.
There are three parts to AmigaOS printing:
1. printer.device - high-level interface that programs use to print
2. Device driver that printer.device uses to communicate with the printer. This could be parallel.device or, in your case, ipp.device (NB: my old ipp.device is here if it helps at all:
https://github.com/chris-y/ipp-device)
3. Printer driver, eg. PostScript. This is the part which converts the output into printer language. In your case this would be pwg-raster.
So printer.device converts the output using the printer driver, and then sends it to the printer using the specified device driver.
In traditional land, it would convert to something like PCL and then use parallel.device to send to a parallel attached printer. In our modern scenario, it needs to convert to pwg-raster and then send using IPP. Your ipp.device might need a prefs editor which scans for devices if you want to use M-DNS/DNS-SD.