No signs of life, liquid damage?

Hello! I recently purchased an iPhone SE 2020 on eBay knowing it does not power on. The sellers claims he charged it one night and it wouldn’t come on in the morning. I opened it up which took a lot of effort as one of the pentalobes was stripped, and inside I immediately noticed a tiny bit of liquid on top of the main board (around the A13 Chip area). No liquid damage indicator was pink/red. I can’t tell if the components under the main board are rusted in the photo or if that’s the normal color but I’m assuming rust… given that the phone shows absolutely no signs of life and won’t even heat up when charging, is there corrosion or what would be likely to short in the board if that’s the case?