In my opinion, it is impossible to completely eliminate the risk of hacker attacks.
However, you can significantly minimize the risk of successful attacks from criminals. Your goal is to create a system to safely store and use your Bitcoins.
This system should be as good as possible for your level of technical competence. By creating unnecessarily complex security, you risk that you yourself will make some kind of mistake that will lead to loss of money. The general principles of creating such a secure Bitcoin storage system are that your funds should be stored in different places (storage diversification) so that one mistake or successful hacker attack does not deprive you of all your capital. Also, special attention should be paid to complete control over private keys (seeds).
Hardware wallets are more secure for storing Bitcoin than smartphones, and smartphones are more secure for storing Bitcoin than laptops and desktops.
This is right that security should not go to an extent that you yourself feel uncomfortable in accessing them. There are few simple things we have to do to secure our Bitcoins. As far as seed security is concerned there is no way better to secure it but to write it on piece of paper. Seed security is first and foremost step in security of Bitcoin. If you have funds then go for Hardware wallets but if you are sticking with mobile make sure it's hardened enough to secure your Bitcoins.