They're your options. Get a new phone (and throw the other one in the bin), or replace the motherboard. It may or may not have been recoverable before you attempted to flash the PIT (we'll never know either way), it definitely isn't now.
If the phone won't boot at all, it's cactus.
You can either pay a Samsung service centre a lot of money to put a new motherboard in, or you can source a 2nd hand one online & either swap them yourself, or pay a local mobile repair shop to do it (cheaper).