Chosen Solution
So I got myself an XS Max some time ago, and around July last year it took a hit by water. On initial symptoms, the screen just started flickering and it became completely unresponsive, had to let it die out (battery drain). I left it the way it was after that for like 2 months, and tried to get a repair/replacement through an Apple Store. Funny enough, I got the chinese model (originally from Singapore), and they told me they could not replace it since it’s from China (first time ever hearing something like this). So I left it lying around for 2 months and then just tried charging it up and using it again, since I wouldn’t get any help anyway. Surprisingly enough, it charged and started up fine, the only damage I could make out was broken FaceID, the mute toggle not working and a 1px vertical pink line. The phone was working fine (this was around August 19). A week ago, the screen went black entirely and wouldn’t work again, probably dead for good. Everything else still works 100% and even the digitizer still does, so I was able to use QuickPlay to make some data recovery. I opened up the phone and tried cleaning the inside and applying alcohol to remove corrosion, display still unfixed. tl;dr: The display is broken after water damage, although it functioned for some time after the initial damage. Now the question is, is only the display broken or did something else (maybe onboard) cause the display issue? Should I replace the display or is the phone too unstable (other damages: FaceID, mute toggle dead, display had 1px pink line) after it aged almost a year after water damage and was used without being cleaned before for half a year? Replacement parts would cost me around 400€ to get them, is it worth the investment on a water damaged 1 1/2 year old phone? (Alternative would be a new/other one) I can also provide pictures of the inside if someone wants to look at it.
Liquid damage needs to be addressed immediately. By not doing so, you may have caused a whole lot of other problems to arise. I would consult with a board repair specialist that way they can examine what’s wrong with it.
