The best idea to avoid theft in the wallet is by picking the right wallet that has a great security which no hacker could open it like blockchain, coinbase, and etc.
Imagine using web wallets, they can easily steal your assets through web wallet. It's not the safest way to store your cryptos, especially on the internet.
You can also use hardware wallet like ledger or trezor that has more great security than online wallets because you are the only one who can access on it, you only need is to not forget your private key and misplace it.
Yea, it's easy to say. But most people are lazy to even buy these equipments, because it costs money and other shit.