"On those that have the Roku Ultra 2024, do you get a notification in the upper right hand corner of TV when when viewing HDR or Dolby Vision content? Do you also see Dolby Atmos logo in same area? I have a LG C3 TV."
I also have a LG C3 and that HDR/Dolby Vision/Dolby Atmos notification is from the TV not the Roku. I have a 4802 Ultra and I see it on HDR/DV/DA programs. It's the same whether I'm watching via the Roku or using the LG native apps.
I have been having same issues on my LG OLED 65cx. Roku support has had no fix for it but the new 2024 ultra is not supporting Dolby Atmos nor is it supporting Dolby vision or HDR content unless you manually force it always on in settings. This never happened on the 2022 Roku ultra. Very frustrating and consuming.
I am not having issues with Dolby Atmos or Dolby Vision. I am getting both from the Ultra 2024.
The notifications aspect was answered above and on Reddit. The LG tv notifies, not the Roku. So, I am good.