It is good to be vigilant but donesn't meant becoming paranoid.
Buyinga hardware wallet like nano or ledger can be safer and cheaper in the same time than buying a smartphone and disable all its features.
You can also store your Bitcoins in different wallets, thereby, if one of them get hacked you don't lose all your money.
Hardware wallet are invonvenient because you need to connect to the internet to use it, mobile phone is simple where you can turn the internet on and off whenever you want without connecting anything.
A hardware wallet you simply plug into any internet connected laptop or PC, nothing inconvenient about that. It's just an USB device, not rocket science

using anything digital that can lose data because of any kind of hardware or software malfunctions is not the "most secure and safe wallet" ever.
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Which is why you keep paper backups of your hardware wallet seed. A hardware wallet basically simplifies paper wallet usage, in that you can store coins with the safety and reliability of a paper wallet, without having to swipe your private keys onto a potentially compromised device once you decide to transmit a transaction.