I would ask here:

https://helpcenter.digitec.ch/hc...

But I would also ask again if it should not work like this (without additional parts).

I would recommend the following links:

https://www.giga.de/extra...

https://support.upc.ch/app...

This should work without additional parts...the TV has a tuner.

But you need the information from UPC, which you should find here:

https://www.upc.ch/de...

Simply enter the address and enter the information during the search...

Try it and if it works, accept this answer, otherwise write again...