Pixel 7 vibrates only briefly after display replacement

After I replaced the display and then switched on the mobile phone without gluing the display, it started up briefly and the display showed the start screen. A few seconds later, the display suddenly went black. I realised that the battery was empty, so I connected a charging cable.

I tried again shortly afterwards, but this time the display remained black. The Pixel 7 only vibrates very briefly.

What could that be? How can I interpret this vibration?

My mobile phone had water damage and when I tried to open it to clean the circuit board, the display cracked.

I removed the circuit board, cleaned it with isopropanol and then reassembled it. The water had only penetrated a tiny bit at the top of the camera module. I don't think the battery was damaged, but can I rule that out somehow?

Many thanks in advance.