I don't know the product "Erard Standit 600", you would have to ask the support at Digitec.
We used the "Vogels Wall 3305 (wall)" wall mount, which caused no problems. All the necessary material was included.
Otherwise, ask user "hjhunziker" who has successfully used this product.
I have had this TV for 6 months. I sit 3 metres away from it and I think the TV could be a little bigger.
So don't worry, your distance is perfectly fine.
Yes, it can be streamed seamlessly from iPhone or iPad or any Airplay-enabled device directly,
it doesn't need an Apple TV anymore, works tiptop.
Greetings Gaetano
Samsung probably doesn't want to pay licence fees for DTS anymore and has dropped support since the 2018 models. An update is unlikely.
The stand has a width of 1242 mm and a depth of 346 mm.