Have you looked at this option yet?
You will need an esp32 board.
Have Mqtt installed and configured in HA.
Have Arduino install on your PC or mac. This is to upload the code to the esp32 board.
Place the esp32 board in bluetooth range to the motion sensor and in wifi range to esp32 board.
I do not have the switchbot motion sensor, but have the door sensor. It takes anywhere between 1-2 seconds. Depending on what you want to trigger, it maybe too long if you are using it to turn on lights. Zigbee or wifi motion sensor device would be faster, however.
Use what you have and give it try. Esp32 is quite cheap if you are willing to wait for the delivery time, but it is still inexpensive if you get it from Amazon.