Read What’s Coming in Betaflight 4.6 – New Features & Improvements. The most interesting for me is the mode to tune PID and filtering during theflight:

The Chirp Signal Generator is a brand new tuning tool that helps you tune your quad’s PID and filtering better.

You can assign this tuning mode to a switch, and when activated, it sends stepped input signals (oscillations) to one axis at a time, first roll, then pitch, then yaw—while you can still fly normally. It starts slow and gradually speeds up, letting Betaflight see how your drone reacts at different speeds.

It was new to me that Betaflight, long known as a multirotor-only flight controller, now also supports fixed wings.