Funnily enough I've been using Codex 5.3 on maximum thinking for bug hunting and code reviews and it's been really good at it (it's just seem to have a completely different focus than Opus.)
I generally don't like the way codex approaches coding itself so I just feed its review comments back in to Claude Code and off we go.
I just created an OpenCode skill where both these models will talk to each other and discuss bug-finding approaches.
In my experience, two different models together works much better than one, that's why this subscription banning is distressing. I won't be able to use a tool that can use both models.
I generally don't like the way codex approaches coding itself so I just feed its review comments back in to Claude Code and off we go.