I did a quick google for you: Other keyboard layouts will probably come in Q1 2021, but I doubt whether there will be a CH keyboard: https://www.raspberrypi.org/forums/viewtopic.php?t=289986

However, the starter kit (US) is available and costs only 10.- extra to the normal Raspberry Pi 400 US. Problem solved.

Only the kit version includes things like cables and a power supply unit. Have a look at www.pi-shop.ch, they should still have some products there.

You're going to want to purchase the mini-HDMI->HDMI cable separately. Possibly also the power-supply and SD card too, depending on if you already have some or not. This is basically *just* the computer and no other components.

The Raspberry is quite capable (has enough power) to watch online TV on it. At the moment, Youtube is running smoothly in 1080p on my Rapsberry Pi 4 (4Gb. model). I'm pretty sure it would also run smoothly in 4K. But if you want to watch Swisscom-TV / Netflix etc. I would recommend the OMSC operating system (OSMC -> Open Source Media Center --> https://osmc.tv). Also, rather forward-looking, buy the 8Gb. Version of the Raspberry. It will need some configuration, it is a developer platform. But it definitely won't take days... rather hours or even minutes.