Firebase is a secure and easy to use mobile backend, and has all the key features to power your mobile applications. Their dashboards and toolkits make it very easy to manage your services.
Open AI is still the best LLM for developers to integrate into their products. Their APIs, tooling and dashboards are far and away the best in the market so far.
Flutter is an amazing framework to build mobile applications. It is fast and easy to develop on and is highly performant. There is also a library for pretty much every feature you need.