Dropped phone into water and shut down automatically after the logo is displayed

I dropped my phone(Asus Zenfone max pro m1) into water then I took the phone out from the water and turned off and cleaned the phone surface with a dry cloth. Then kept my phone in a pouch with uncooked rice for 4 days. Now I try to turn on it shows the logo and shutdowns automatically. Even I tried to enter into the recovery mode but got failed. But I can enter into the fastboot mode. When I try to charge, the charging indicator fluctuates. Can anyone tell me what is the issue?