@pastrychef I am glad to say that I resolved the DisplayPort colour banding issue and confirmed the results by observing the interface in Dark Mode carefully, including sidebars and Launchpad. After multiple restarts, colour banding still no longer happens.
The steps are incredibly simple without any technical skill.
- Open Hackintool
- (If it is on macOS Catalina or later, switch to the Tools tab and press Disable Gatekeeper and mount the disk in read/write mode)
- Switch to the Display tab and just export without changing anything
- As Hackintool has generated 3 files and 1 folder to Desktop, just drag the folder DisplayVendorID-xxxx to /System/Library/Displays/Contents/Resources/Overrides
- Restart
If the results remain fine after one week, I will mark this topic as Solved.