The bitcoin network is safe. It was never hacked. Threads and titles like yours are the ones that spreads FUDs and rumors. A quick google search and reading a news from an authentic source might have answered your question. The FBI probably seized the wallets with the private keys. Not hack them.
No they can't confiscate your funds as long as you don't give them your private keys. But if you store your coins on a custodial wallet, the organization that has access to your keys might give it to the FBI for legal reasons.