I agree. However as you said, you can consider code agents like human contributors. My feedback is that an army of Claude Code instances with a strict CLAUDE.md file is more rigorous than a human team.
I recently came across https://claudecode.run/ (not affiliated). There are currently several similar products that help that multi-instance Claude Code layout
How quickly? There is no limit to that. If I can do my day of work in few hours I would be glad to take the afternoon off or to go twice as fast (importunately that's more the second!)