What do you think is the problem? I think the problem is water damage. You have a collection of dozens of parts that may have been exposed to water, and you have a logic board that itself is hundreds of corrodable components soldered in place. We have no way to say "it's cap C1531 bro" without looking at the phone.
If you want to fix it your options are to take it to Apple and pay for out of warranty swap. Or you can DIY fix--open it up using iFixit guides and start troubleshooting. Or you can take it to an independent repair shop that will have known good parts and new parts and pay them to troubleshoot it for you.
Like Piotr says--software restore is a waste of time. You can't solve hardware problems with software solutions. You know water got into this phone. Without opening it and cleaning it, applying voltage into a phone can only make things worse.