Hi Torvics023,
Thanks for reaching out to Apple Support Communities. It sounds like you're having an issue with the display on your iPhone 12 Pro Max. We're happy to help.
If you check your accessibility settings are you showing any vision settings such as Invert Colors are enabled? You can navigate to Settings > Accessibility > Display & Text Size to double-check. If needed, the article here can also assist with checking other vision features: Use display and text size preferences on your iPhone, iPad, and iPod touch
If the feature is turned off, does the issue continue after a normal restart of your device? Check here for those steps and additional steps to help: If the screen isn’t working on your iPhone or iPad
You can also view helpful information to check additional vision settings from the guide here: Get started with accessibility features on iPhone
Cheers!