I guess you’re talking about some Goodix Bluetooth chip that has a Cortex-M4F? Exact chip name still unknown.
You need know quite a bit about PlatformIO to be able to create your own platform, framework builder, board definition, etc. I’d recommend reading through
- Custom Platform & Board — PlatformIO latest documentation
- how PlatformIO builds a firmware
- other platforms that deal with ARM Cortex-M4 chips like https://github.com/platformio/platform-ststm32/, https://github.com/CommunityGD32Cores/platform-gd32/, https://github.com/platformio/platform-raspberrypi/, https://github.com/platformio/platform-nordicnrf52, …