GPT-6 Astra Pro and Solar Pro 4 are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
GPT-6 Astra Pro, from OpenAI, has a 1,050,000-token context window and is priced at $10/M tokens input, $50/M tokens output on OpenRouter.
Solar Pro 4, from upstage, has a 524,288-token context window and is priced at $0.03/M tokens input, $0.12/M tokens output on OpenRouter.