Has anyone been able to solve this issue?
YES! Basically, you have to update the firmware for the monitor. I have the 32UN880-B connected via USB-C to a MacBook pro 16" 2019. Initially, the display would auto-dim constantly and noticeably about once every few seconds. I had no luck using the monitor click-wheel for settings - general - Smart Energy Saving = Off. This setting was grayed out while connected to the MacBook, so I switched the monitor input to HDMI (nothing connected to hdmi) which ungrayed the smart energy saving so that I could turn it off. The out of control auto-dimming continued. So to be clear, the problem wasn't the energy saver. What solved it for me was updating the monitor's firmware. You do this by googling 'lg monitor drivers'. The first result is "Software, Firmware & Driver Downloads | LG USA Support". Go there, type this in the website's "Find Software & Drivers by Model" search field: 32UN880 and click on the first result. Now you should be viewing the page for "32UN880-B.AUS". I downloaded "[Mac OS] OnScreen Control - version 6.04: Mac_OSC_6.04.zip", installed it, and answered yes to all of the mac's warnings about 'allow this software control your computer'...there were several of these. Then, go into Finder - Applications and open "OnScreen Control.app". After a few seconds, the app popped up a messaging saying it detected a "Monitor software update", so I told it to install the update. If you don't see the message, use the menu on the left to choose "Monitor settings" and at the bottom of the page is a button to press called "Monitor Software Update - Run". This will trigger the software update, or else a message saying your monitor software is currently up to date. My updated firmware version for July 2023 is "3.03, 1.2.16, 4.11". The installation took an unusual amount of time, about 20min, and at the end it had me unplug the monitor's power cable and plug it back in, and I think also restart the computer. After that, the auto-dimming insanity completely stopped; the monitor is now behaving itself. Just a note, for the "OnScreen Control App", there is a tiny settings button in the upper-right that allows you to disable 'Auto Start' and "Auto Update" if you wish. I personally have no intention to use on screen control, but you might like it since the app ALSO gives you the ability to auto-arrange windows within certain 'zones' on your screen, similar to the built-in feature for windows computers. Hope this helps anyone else out there encountering this issue. The monitor is wonderful now that the auto-dimming bug was fixed by that update.