Isn't that essentially Dia? (Pro is 20USD/month.) https://www.diabrowser.com/

(I miss Arc, such a shame it only gets security/chromium updates now ...)

And I think Codex's desktop client has a built-in browser now? At least I've seen someone using something like that. Nevermind Atlas is a thing now too. https://openai.com/index/introducing-chatgpt-atlas/

(Tell me if I'm misunderstanding you?)