Questions about Value Network cable

This is indeed a 20 metre cable. :)

If the route is completely straight, i.e. no room corners that could kink the cable: At most YES But today I would most likely go for Cat6/Kat6a Slimline or Flat, of course U/FTP. Unless you have large power consumers between the router and the TV box...

Yes.

Unfortunately, we do not have more precise information on the transmission rate. Enclosed you will find more details about the product. Maybe this will help you. http://static.mercateo.com/7c/073220eb978142abaf981c6b9195588c/pdf/21990315_de_epim_data.pdf?v=476

According to the data sheet, the cable has a diameter of 5.4mm: https://www.secomp.ch/data/i2cmsdata/pdf/s21/21990520_en_data_scmp.pdf

Cat.7 = 10Gbit/s

Actually the price of 1m cable doesn't make sense either.