How to access DeepSeek and Qwen alongside OpenAI without managing separate API keys for everything

This is a problem I spent longer on than I should have. We run a mixed model stack. DeepSeek V3 for the cost-sensitive tasks, Qwen 2.5 for multilingual, GPT-4o for the things that actually need it. On paper this sounds fine. In practice managing the API layer for all of these became a part-time job