LG TV, AppleTV 4K (3. gen) and Bluesound Pulse Sounderbar+ NO SOUND!

My setup is as follows:

LG TV (an older one)

AppleTV 4 K (connected to HDMI 2 on LG TV)

Bluesound Pulse Soundbar+ (Connected to HDMI 1 ARC on LG TV)

When I start my AppleTV to watch any shows (local TV stations, Netflix, you name it) I have to select my Soundbar as sound source in the AppelTV Video and sound settings. The Apple TV won't save my choice. Can't see where my problem is with setup being as it is. There is no sound at all befor I do the sound changes. The settings on my TV are set to Automatic under it's HDMI/Digital sound settings.

My Oppo Blu-ray player is connected to HDMI 3 on the TV and here there isn't any soundproblems at all.

Thanks in advance