Hi @MaximeDoireau, welcome to the Sonos community. Thank you for reaching out to us and letting us know about your concern. Let me help you with this.

Appreciate your interest in Sonos products. The Sonos Arc, 2 Sonos Ones, and a Sub will give you a 5.1 home theater setup. Allow me to share some features of the products. The Sonos Arc can play Dolby Atmos audio. ARC and eARC are protocols responsible for sending audio over an HDMI cable to home theater sound systems like Sonos Arc. Sonos Arc must be connected to HDMI ARC or HDMI eARC to play any Dolby Atmos content. You can find more information on playing Atmos audio through Arc in our Dolby Atmos article.

Some streaming service content such as Netflix is streamed with Dolby Digital Plus surround audio, which is only supported by Sonos Arc. DTS audio format which is not supported by Sonos. Some players and game consoles have the ability to transcode DTS into a format that Sonos supports, such as Dolby Digital 5.1. You may also need to check this article about unsupported audio on your home theater speaker for reference.

Hope this helps. Please do not hesitate to reach out if you have further questions, additional feature requests, or concerns. We are always happy to help out.