Help with Atmos audio output from PS5 to Sony soundbar

[MrL1992]

My current set-up is PS5 -> Sony HT-ZF9 soundbar -> 2017 Samsung TV (via ARC)

I have tried playing three different Spider-Man 4K blu-rays, all with Atmos mixes (also listed as compatible with Dolby HD) but when I check the audio output by pressing 'display' on the soundbar remote, it keeps saying it's LPCM 7.1 surround audio. Even when I change the audio output priory to Dolby bitstream, it makes no difference. 

Is there something I'm missing or misunderstanding? Or is this a software issue with the PS5 or soundbar?

It's Sony movies on a Sony player using a Sony Soundbar so if I cannot get answers here, well...

[MrL1992]

Update 1

i found the Blu-ray player settings menu on the PS5 along with the option to select the audio format between LPCM and Bitstream however the latter is greyed out, not a clue why?

[MrL1992]

UPDATE 2

The cause was the Screen Narration feature in Accessinility which forces all system level apps into LPCM. The system suitors really warn you of this.