alt Hacker News> ChatGPT web UI was also like this for the longest time
Copilot Chat has been perfect in this respect. It's currently GPT 5.0, moving to 5.1 over the next month or so, but at least I've never lost an (even old) conversation since those reside in an Exchange mailbox.
I lost thousands of conversations I'd had back in the move from "Bing" to "Copilot". Moved straight to Claude and never touched a GPT again.