karabiner-elements is one way to customize the keyboard keys. You have to start with basics and you might end up with your favourable customization

Hex-Input works well for most users. However, for those who want to highly customize their keyboard keys, installing a tool like Karabiner-Elements is an excellent choice.

Karabiner-Elements allows for extensive customization of keyboard keys. To get started, you'll need to begin with the basics, but with some time and effort, you can achieve your preferred customizations.