I had the original ChatGPT app and I was also "upgraded" to the new unified ChatGPT/Codex app.

The old ChatGPT app had been very wonky lately and not working correctly. For example, I was unable to switch the mode to "Thinking" as it was stuck on "Auto". I was forced to use the web version for the last few weeks.

So today I was offered the new unified app and decided to try it. Within 5 minutes I had regretted this decision. I ended up deleting the new app, but the old app is also gone.