Google translated your post :)
Here is my system setup which is close to what you want and it works well.
1. I use an Apple TV 4K connected to a Sony OLED TV via HDMI (Apple TV is both compatible with AirPlay 2 HDMI CEC so you need Apple TV remote gold app)
2. I use the digital output variable from Sony TV (if your TV does not have any audio input on your headphone jack on the TV) and connected to BL 8000 using the stereo to RCA L / R cables. These cables are easy to find ...
3. The Sony TV has the option to send audio to all audio sources simultaneously. This effectively lets the TV's acoustic surface speakers act as the center channel with the BL8000 being L / R and you end up with a much wider sound stage. The Sony TV has an inbuilt subwoofer so the overall effect is better than just the BL8000. If you send audio to the Apple TV via AirPlay 2, the HDMI CEC feature will wake up the speakers and you are good to go!
4. While the BL8000 lacks for proper bass. To correct for this I added a BL2 subwoofer to the mix. So the connection is now TV to sub and sub speakers. Sounds Heavenly provided the cables. Problem is that the speakers are now ready to be turned on and off. The bass is much better though ...
5. Since I had other B & O speakers around I had an experiment to chain 2 x BL2, 2x BL 8000 and 2x BL6000 in this exact set with an additional stereo splitter going to my TV. So I'm up with Left Going to 1BL2, which connected to a BL8000 + BL 6000 and right doing the same on the other side. The overall sound was pretty impressive goal I think I was more than happy to be all over the world when using AirPlay 2!
6. To end it all ... I did a final experient where I did the same Apple TV and Sony TV but switched the complex BL8000, BL 2 and BL 6000 config with 2 A9 beoplay speakers. Both speakers were placed as L/R next to the TV. I could get perfect AirPlay from Apple TV to both speakers with no audio sync issues AND when wired as L/R the A9 sounded better! All-in-all...the newer B&O speakers are just better so whatever DAC you use (Connect is not a good DAC) you're running up against the BL8000 quality...