Apple replaced my phone for free after 3 days of going back and fourth with them. First went to the store and they told me it was water damage and they couldn’t do anything without me paying $700. Next I called apple and educated them on my issue, spoke to them calmly and without disrespect. They understood my issue, I pointed out the Sep 2018 keynote where they spoke about the device being rated ip68. I also pointed out how the reps at the store deemed my phone water damaged but couldn’t prove to me that the water strips were triggered. (They weren’t triggered) I know for a fact the XS MAX is defective, I’m happy I got a new phone but it sucks I have to treat it like a first gen iPhone when it comes to being close to water.
Go check out the September 2018 keynote, FF to 40:30. That might help with your false advertising lawsuit. I pray it helps, I’m having the same issue with my xs max right now and it’s only seen wet hands after showering and some rain while I’m at work. My iPhone 5s saw ALOT more water than this XS MAX and never had any issues! Matter of fact, that old 5s is still alive and well and loved by my mother. No doubt in my mind this model is defective.