As a user of calibrated IPS panels forever, here's my personal preference for accurate colours and perfect balance of everything (to my eyes anyway).
Preset Mode: Creator with sRGB colour, 2.4 Gamma
Brightness: 53
Contrast: 66
HDR mode: Peak 1000
In Windows make sure that the display settings are suitably set and any Dell colour profiles are removed with colour preference set to "use my settings" as shown below. I prefer 10-bit colour and in srgb as I edit a lot and want maximum colour bandwidth - 10-bit means you are running at 144Hz instead of 175 (8-bit) so if that's not a problem, then stick to that otherwise you can use 8-bit and the GPU will dither effectively. I found personally that at 175Hz I could see some flickering in some games when certain dark grey tones were dominating the screen. At 144Hz this is completely gone. I read this is due to the use of the Gsync module as it's an old module now. There is no noticeable performance difference between 144Hz and 175Hz that I have found in desktop or gaming.
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When using Windows have HDR mode turned off in Windows. OS level HDR in Windows is patchy, so only use HDR when gaming or watching a movie that is in HDR. Many games now auto trigger the SmartHDR function and will go back to normal mode when you exit the game. Likewise if you use MPC-BE with the MPC video renderer then that can be set to do the same thing when a HDR video is opened.