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.
Yes. As long as your private key is secure, no one is going to steal your coins. Actually it is not that hard to keep your coins securely. But a lot of people are careless with their wallets, and in such cases, the hackers may find it easy to access your coins. First of all, the basic precautions needs to be followed, such as enabling 2FA. And along with keeping the wallet secure, please keep in mind that properly backing up your wallet is also very important. I have seen a lot of cases where the coins become inaccessible because the user can no longer log-in to the wallet (password forgotten, email access lost.etc).