Ah, okay.
Use the HDMI 2.0a port, to enjoy HDR features. Apparently, only one of the four ports on the tv supports that. Probably the one marked “UHD”. Get (at least) matching cables (HDMI 1.4 ‘High-Speed’ or better). Some find their old 1.4 cables not up to spec for HDR, I don’t know, it should work, but apparently not for everyone.
Switch the tv to use that HDMI port for input. Not sure if you can do it on the Loewe remote blindly, or perhaps you need to access some Sources menu on screen, where you can access e.g. ‘HDMI 4’.