Display is rendering colors as negative images on Home Screen and in apps

Check: Settings>Accessibility>Display & Text Size ... and turn off ALL the options there. When done, restart your iPad.

If the issue persists, it might be a hardware (screen? other internal component?) problem, but we, just users like you cannot diagnose that kind of issue remotely.

I suggest that you make an appointment (*) and have your device inspected at an Apple Store or AASP (Apple Authorized Service Provider) among this list:--> Apple – Location Selector. After checking it out, they'll give you all the available options.

Regards

Giulio

(*) You can do it:

• Online:--> Genius Bar Reservation and Apple Support Options - Apple;
• Contacting a local Apple Store or AASP among the list provided above;
• Using the "Apple Store" app, available and downloadable from AppStore.

If the screen colours appear to be distorted or unnatural, you need to check some key Accessibility settings that are intended to compensate for specific colour-vision issues:

Settings > Accessibility > Display & Text Size

Ensure that all settings enclosed within the red box above are switched OFF/Disabled.

Otherwise, depending upon your installed version of iOS/iPadOS, you’ll need to look at your Dark Mode settings:

Settings > Display & Brightness > [Appearance]

I have spent hours trying to figure this out. Thank you so much. A grateful heart

You are welcome