Seems like I may have found the problem, the latest Google Messages Update does a "stealth install" of two additional apps with zero notice to the user. They are "Android System Key Verifier" and "Android System SafetyCore"
I looked them up, SafetyCore is a "security" (yeah right) feature that says it scans your device for "unwanted content" (in reality it just scans your device for more personal data to link to your profile so Google can charge more $$ selling it to ad companies) and Key Verifier is some service that lets apps verify a message contacts public keys.
For whatever reason, either one or both of these apps drastically turn up the brightness, gamma, and contrast on the screen leading to searing eye strain. Blacks are WAY deeper, white text on a black background is drastically brighter, and the overall gamma is cranked way up. I found both the apps in my app list, cleared their cache, deleted their data, removed the apps, rebooted the device, and it SEEMS to be fixed now. I can't tell if it is 100% back to where it was since I have been in constant pain triggered by this damn phone for 3 days straight so my facial muscles are all jacked up, but it's at least 80% better and it may get back to 100% after a few days eye rest. I am also prepping the device and backing up all my data and APK's and version lists in the event I need to do a factory reset to completely get me back to stock.
So just a heads up, be very careful before updating Google Messages if you use that app. My overall worry is that since these are "system" features, Google is likely to roll them up into Android itself in the future and there will be no removing them without rooting the device which is getting harder and harder to do. But I guess that's a problem for another day
Edit: to the other folks replying, the phone was not updated, I have Developer Options enabled, Auto Install Updates disabled, I disabled the System Update app, and confirmed the system version was the same it has always been on the device. I took a screenshot of the system version the day it came out of the box so I can always verify.