According to reports, gamers are unable to get their PS5 to play 4K with high dynamic range (HDR) onto their TVs. They could either play at 4K by disabling HDR or play at 1080 with HDR on. PS4 Pro and XBOX x series consoles showed no such behavior. This was more of a connection error than a console issue. It was noticed that users reporting this had their console connected through AVR or soundbar. Also, you need to be sure that the console is connected to the correct HDMI Port on your TV. Alternatively, you can enable HDMI Enhanced/Deep Color setting for the HDMI port the PS5 is connected to.
Some users reported a 4K HDR output issue related to soundbars as well. For a workaround, you could use a device with multiple HDMI output channels, one connected to your TV and the other to your soundbar. PS5 should be connected directly to the TV onto the correct HDMI Port.
“The issue with these can potentially be worked around by connecting the PS5 directly to your TV and then running the sound out of the TV to the soundbar via ARC technology (assuming your TV supports that). This solution is far from ideal, though, because the affected soundbars don’t support eARC technology for lossless Dolby Atmos audio passthrough, and some especially older TVs don’t support Dolby Atmos (which the PS5 can play from 4K Blu-rays) passthrough over ARC at all.”-Forbes
If you are facing this issue related to sound bar, I would recommend this video.