我发现了这个问题，并想出了一个解决方案。显然，PyAudio不允许你更新设备列表而不重新初始化它。我不知道是否有人需要这个，但这里是我的解决方案：
我只通过再次调用PyAudio来更新设备列表。因此，创建如下def：

def init_py_audio():
    # Opened for the first time
    if py_audio is None:
        py_audio = pyaudio.PyAudio()
    
    # Refresh
    else:
        py_audio.terminate()
        py_audio = pyaudio.PyAudio()

此外，在获取设备列表之前，请按如下方式调用它：

import pyaudio

py_audio = None

def get_mics_list():
    # Better use it inside a class and don't use global
    global py_audio

    # Opened for the first time
    if py_audio is None:
        py_audio = pyaudio.PyAudio()

    # Refresh
    else:
        py_audio.terminate()
        py_audio = pyaudio.PyAudio()

    mics = []
    info = py_audio.get_host_api_info_by_index(0)

    # List all devices
    for i in range(0, info.get('deviceCount')):
        # Check number of input channels
        # (If there is at least 1 input channel, then it is suitable as a microphone)
        if py_audio.get_device_info_by_host_api_device_index(0, i).get('maxInputChannels') > 0:
            mics.append(py_audio.get_device_info_by_host_api_device_index(0, i).get('name'))

    return mics

# Will update the device list every time it is called
print(get_mics_list())