The Bluetooth name, Wi-Fi Direct name, and device name change instantly when the personal hotspot name on my phone is changed

Cause:

The Bluetooth name, Personal hotspot name, Wi-Fi Direct name, and Device name keep the same. Once you change any name, the other names will change as well.

This helps make your device names consistent and easy to recognize, and does not indicate an issue with your device.

Related question:

Do I need to reconnect to a personal hotspot and enter the password after changing the personal hotspot name?

Answer: Yes

Related knowledge:

My HUAWEI phone/tablet can't find my Bluetooth earphones or speaker