This is possible with an EF to RF adapter. However, without an adapter you cannot attach lenses with an EF mount directly to an RF camera. With the adapter, however, the lens works perfectly

No, the promotion does not apply to the EU version.

Technically speaking, cameras with the same name are identical. The "EU model" is simply from the "CH cashback promotions" and the 3-year CH warranty from the manufacturer, should the corresponding product receive one. Otherwise they are the same. We offer CH and EU models, as this increases availability (at different prices), which I can well imagine is the reason.

Technically, the product is the same, but with the CH version you can benefit from the extended Canon Switzerland warranty (requires registration of the camera with Canon Switzerland after purchase)

Thank you very much for your feedback. The Canon EOS R8 has 24.2 megapixels, I have just adjusted it.