A: No daily query limit -> As the name suggests, it wont be capped.
Unlimited with your API keys -> This is applicable for certain models which we may introduced in the future, which are expensive and it won't be sustainable for us to offer them as unlimited (e.g. GPT-4.5 has an API price of $75/1M input and $150/1M output)

For the currently offered Ultra models including DeepSeek R1, Gemini 2.5 pro, Gemini 2.5 Flash, O4-mini etc - you do not need API keys.