Samsung 65" QN90A Dark Square and Flashing

I have a 65" Samsung QN90A (QN65QN90AAF) that developed a [dim square and the entire screen flashes bright/dim rapidly](https://i.ibb.co/ymdKShwG/PXL-20240608-042412824.gif), both showing up at the same time. I am well outside of my warranty window.

I opened up the TV and didn't notice any singed or burned components. Unplugging the wire going to the dim square from the driver board did not stop the flashing.

I'm hoping it's just the driver board, but don't want to start throwing money at it without some advice from those more knowledgeable about TV repair than I am.

Do you think this is something fixable that won't cost an arm and a leg (this was already plenty expensive when I bought it in 2021)? I am pretty handy with electronics and do have the capability to solder, if needed.

The TV is currently put back together, but I do have additional pictures of the various boards if they'd be any benefit and can take the back off again if additional information/troubleshooting is needed. Feel free to ask any questions...

Thanks for any assistance you might be able to provide.