Autonomous navigation UAV

Hi, I am actually working on an autonomous navigation quadcopter system. I have simulated my systems with Gazebo and ROS2. Now I would like to do the same with a real drone. I don’t know what hardware is needed or how to procure it. I have seen that most UAV have a flight controller. Is it possible to communicate with this flight controller from a microcontroller? Actually, I want to connect my microcontroller to the flight controller, then my PC to the microcontroller with wireless communication. With this configuration I want to be able to run my calculations on my PC and then send the flight data to my flight controller (for example, the speed along an axis). Does this approach seem possible? Are there easier ways to do this?

Yes, all that you want to do is possible.
And easy to do, but you need to read and learn new things.