My anecdotal experience with a recent project (Python library implemented and released to pypi).

I took the plan that I used from Codex and handed it to opencode with Qwen 3.5 running locally.

It created a library very similar to Codex but took 2x longer.

I haven't tried Qwen 3.6 but I hear it's another improvement. I'm confident with my AI skills that if/when cheap/subsidized models go away, I'll be fine running locally.