#1 it has warranty, you'd just have to send it to China in the extremely rare case that you need to
#2 I'm pretty sure global roms have Google pay (I'm in the 99.9% of android users that don't use it though, so I haven't checked)
#3 But it has WAY better audio quality than the S8 with the USB c adapters (Snapdragon Samsung phones have horrible audio)
#4 IP rating means literally nothing. All that shows is how the phone performs in pristine condition under very specific circumstances. If you drop your phone one time it can break the waterproof seal and ruin that precious IP rating
Meanwhile if you get the S8 you're getting a tiny phone with a 2 year old CPU, a 3 year old camera that wasn't even upper echelon when it came out, only 4gb ram, vastly inferior aesthetic design and a gross curved edge screen.