On your last point since DeepSeek v4 supports Claude Code's API you can literally set a few environment variables and continue to use Claude Code as a harness.
Like you say a combination of frontier and cheaper models is probably the optimum and that would require setup if you didn't want to choose models manually each time.
Like you say a combination of frontier and cheaper models is probably the optimum and that would require setup if you didn't want to choose models manually each time.