Mac Studio 2023 HDMI to Dell Ultra sharp U2723QE monitor outputs 4K at 24 bit RGB

From what I'm reading on third-party sites, M1-family Mac Studios have HDMI 2.0 ports, and M2-family Mac Studios have HDMI 2.1 ones. You say you have a "Mac Studio 2023" – so presumably it is one of the M2-family models that has a HDMI 2.1 port.

The Dell UltraSharp U2723QE manual says that it has a HDMI 2.0 port (page 15: "About Your Monitor").

It looks like with HDMI 2.0, for 4K displays, there is a tradeoff between

• Refresh rate
• Bit depth
• Chroma sub-sampling

To get 4:2:2 or 4:4:4 sub-sampling, you must give up either 50/60 Hz refresh rate, or 10-bit/channel color depth. 4:4:4 means that each pixel has its own color information. 4:2:2 means that you are forcing groups of two pixels to share the same color. 4:2:0 means that you are forcing groups of four pixels to share the same color. Or to put it another way, 4:2:2 and 4:2:0 would appear to reduce the effective resolution of the display.

https://www.extron.com/article/hdmi2faq

https://www.eaton.com/us/en-us/products/backup-power-ups-surge-it-power-distribution/backup-power-ups-it-power-distribution-resources/cpdi-vertical-marketing/hdmi-explained.html

I would guess that because the U2723QE only supports HDMI 2.0, the Mac has chosen (60 Hz refresh rate + 4:4:4 chroma sub-sampling where each pixel has its own color) at the cost of 10-bit-per-channel color.

You can certainly use a USB-C (DisplayPort) to DisplayPort adapter cable. Hopefully it will give you 4K resolution and 10-bit (per channel) color depth at 60 Hz. If you're getting that right now from a USB-C to USB-C connection, it follows that the Mac can output that over USB-C if the device (monitor or adapter) can accept it.

I'm not sure where "12 bit depth" is coming from. The monitor supports a color depth of 1.07 billion colors (page 14). 2^30 = 1,073,741,824 – so the reference is clearly to 10 bit (per channel) color depth.