No setting for default homepod pair on Apple TV - temporary only

Equipment:

Apple TV A1625 (64 GB) - which I believe is the Apple TV HD 4th gen

2 brand new Homepods

Samsung Frame 55” TV

My Homepods are setup in the Home app in the same room and are paired with each other.

When I try to add them to Apple TV to use as a pair of speakers, I cannot add it as default. They can only be added as Temporary in Settings > Video and Audio > Audio Output. They’re brand new; they’ve been doing this for the past month since I got them. As temporary speakers, it reverts back to the default (TV Speaker) frequently and I have to manually go in and select the Homepods under Audio Output or under the control menu in the upper right. There is no option other than TV Speaker under Default.

What am I doing wrong? I do not want to have to manually select the correct speaker every time I use the Apple TV.