The chip can be programmed with Arduino.

The Arduino package is based on arduino_core_ch32. However the upstream is stall and I have to fork myself. 

An up to date package can be installed from

 https://github.com/DeqingSun/arduino_core_ch32/releases/download/arduinoPack/package_ch32v_index_add_ch573.json

There is BLE example (included in Arduino package) on https://github.com/DeqingSun/arduino_core_ch32/blob/add_ch573/libraries/CH573BlePeripheral/example/example_ch573_ble_test/example_ch573_ble_test.ino

You can either export binary and use WCHISPTOOL to flash the chip, or you can just select the Upload Method to "WCH-ISP" in Arduino IDE, and manually put chip into bootloader mode and flash it over USB (not on CH571K yet). 

Note the example also include the USB-CDC code. That means if you are using a CH573/CH571 with USB port, you may simply choose the USB serial port in Arduino IDE and it can go into bootloader mode automatically, and do the flash. Just like Arduino Leonardo.

Here is video of the control over WebBluetooth, https://deqingsun.github.io/Javascript-Signal-Processing/bleFunctions.html