Have you seen openrouter.ai? They are more or less based around that idea, I think. Routing to whatever is best fit - most likely on price, I’d think (?) and/or currently up.

I have not set it up myself, but I think there is a way to have opencode or the like prefer local models for certain things, then escalate to something remote (presumably paid) if needed.

Also, opencode.ai gives you so many free tokens per day on some of their models.