Isn't Codex TUI available for free though? Besides others like Pi and OpenCode of course.

It can use local/oss models, but it doesn't make it simple to do (easiest with ollama) and it's not clear what else you 'lose' by making that choice.

If you had a really good (big) local model, maybe it's an option, but on the more common smaller (<32b) models, it will have similar problems in looping, losing context, etc. in my experience.

It's a nice TUI, but the ecosystem is what makes it good.