Doesn’t turn on after water demage and removing all shorts

Water damaged devices can have multiple issues. Have you checked the PMIC output voltages?

The PMIC generates ~15 voltage rails. They are all important (for obvious reasons) but the ones to check first are as follows: PP_CPU, PP_GPU, PP1V8_SDRAM, PP1V2_SDRAM, PP_VAR_SOC, PP0V95_FIXED_SOC, PP3V0_Tristar, PP3V0_NAND, PP1V8_ALWAYS and PP1V0.

If that looks good, you can also check the BBPMU as well as the secondary outputs on the PMIC. Not all water damaged phones are repairable and sometimes the issue is internally damaged IC’s that will not give you any obvious clues.