If you want a ChatGPT app that works well with Siri and Shortcuts, Short Circuit is a top contender. The app provides a unified ChatGPT experience on iPhone, iPad and Mac, and it works well with Siri through the "Ask Shorty" command. It also works with Shortcuts for more complex sequences of actions, so you can use AI in a very customizable and automated way.
Another contender is iChatWithGPT. This personal AI assistant is designed to work on multiple devices, including iPhone, Watch, MacBook and even CarPlay through Siri. It's got a lot of features, including web research, answering questions and sending text reminders, all through voice commands to Siri. That makes it easy to fit into your life.
If you prefer a browser-based approach, Lunabot is a powerful AI assistant that can boost your productivity with its shortcuts and custom commands. It works with multiple browsers and even Telegram, and Lunabot can be triggered with Siri voice commands. It's a good tool for a lot of different tasks. It's available in different pricing tiers, including a free version, so you can pick the level of utility you need.
Last, TextGPT is worth a look, especially if you want to use ChatGPT in the iPhone's built-in messaging app, iMessage. The app brings expert knowledge and creative tools to your text messages without requiring you to install another app or fiddle with an API token. That's handy for quick uses on your phone.