As far as I know Bitcoin cannot be hacked as long as no one can know your seed phrase or private key. To secure this, it is better to save or write this one in a piece of paper or somewhere in the cloud that you think is also secured to save personal information. Though there is also a risk of saving files or information over the Internet. To avoid being hacked, just avoid clicking unrecognized emails or websites.
It is so true, a private keys was so important and better that no one knows your seed phrase and much better to have a note or write it down all important details on a secured notebook in which whenever you forget any important details you have a copy of it that you can look back in case. Well, it is much better to keep your keys so privately than keeping your wallet connected online as always because hackers were too good to hacked account so better be safe than sorry.