After water damage repair still dead

Hello, my iPhone 5s has suffered water damage a few days ago. I let it dry on room temperature. On Saturday I opend it to clean the logic board with 97% Isopropanol. I also cleaned all connectors.

After I removed the logic board, I removed the EMI shields with my hot air station on 330°C. On the back side with the large EMI shield, I saw some stain from the water. So I put the board in a Isopropanol bath for 12 hours. After 12 hours i turned the logic board. After further 12 hours, I cleaned the whole board mit a clean toothbrush. After further 6 hours, I let the board dry on room temperature for 24 hours.

After the Isopropanol bath, the logic boards looks like new. So i decided to resolder the EMI shields and build all parts back in the iPhone. I also changed the battery but I got a battery with the wrong APN.

Now I can't start the phone as before. :( Push the power button = nothing, connect the phone with my pc and iTunes = nothing.

I'm not sure what to do now? Is the APN so important that the phone can't start with the wrong APN battery? Do I have to clean the whole board again? Is it recommended to replace the docking connector and display too or is it a waste of money?