Iphone XS Max suddenly dies with battery life left

I purchased this phone brand new and have always tried to perform charging when it dropped to 20% and removing from charger at 80%. I am up to date on patching right now and that is my standard practice. My battery health says 92% in settings. Starting about 1 - 2 weeks ago on two occasions my phone screen was suddenly black and I could not get any response until I plugged it in to power. In both cases I had no recollection of power at a critical level and no warning of shutdown. When it powered back on while connected, both times power level said 13%.

With that in mind I started keeping a closer eye. Today I noticed power at 33% while I was listening to an audiobook on speaker. I stopped it to shower and then a few minutes later I turned it on while getting dressed. Next thing I know, sound stops, screen is black and phone has died even though there should be no way the power went down that fast.

At least one update was applied since this started as a new one just came out. Battery has been taken care of by me charging it in the manner I understood to be best. Any suggestions out there?