The best way to access ChatGPT "chat" was always on ChatGPT.com via a web browser, not even the iOS app seems to have all the little things you can do on the web version.

The Mac desktop ChatGPT app had weird issues like not being able to see the model being used by a chat inside a project etc. I just ended up installing ChatGPT Atlas and using that as an AI-only browser for all LLMs including Claude and Grok lol

Always was better IMO. I just pinned the browser app as a desktop app and have been using it that way for many months. Works great.