Playstation 4 and soundbar! Problem connecting to TV, what am I doing wrong?

I need your advice.

I got a fat OLED TV from LG especially for the upcoming PS5. Everything so far fine:-) My Sony HT NT5 soundbar and the Sony SRS-ZR5 multiroom speakers are connected to the TV via the ARC port as rear support. The soundbar turns on of course as it should be via the TV. Everything so far good!

The only problem I have is that as soon as I connect my Ps4 to the TV, the soundbar switches off and I can only hear the sound through the TV speakers.

If I pull the HDMI out of the PlayStation again, the sound goes through the soundbar as normal.

I got a TV with HDMI 2.1 because the new PS5 needs it.

The plan was that I would connect the soundbar to the TV via the normal ARC HDMI port and the Ps5 to the TV via HDMI 2.1 and that I could hear the sound of the Ps5 via the soundbar!

What am I doing wrong?!

After connecting the PS4, you should go to the sound settings of the TV and switch there (again) to OUTPUT via the sound system instead of TV speakers. I don't know whether this can be permanently set.

I've tried everything… As soon as the Ps4 is connected via HDMI, the sound on the TV can only be heard through the internal TV speakers. PS4 then runs on the soundbar, but the sound for the normal TV program is only possible via TV speakers. As soon as I unplug the Hdmi of the Ps4, the sound from the TV program runs through the soundbar again