In my opinion, the upscaling also works with DVD playback. When playing a DVD, DVD-Video Playback 4K is displayed in the Playback field (according to the operating instructions, an HDMI cable with 18 Gbps is required for this).
According to the technical data from Panasonic, only Region 2 and ALL are supported, I don't have any Region 3 DVDs and unfortunately can't test it.
Hope I could help so far, LG.