F10 can only be used to open PC Manager when there is a PC Manager installed. If you have uninstall PC Manager, pressing F10 will not help you open the app . To resolve this issue, install PC Manager again and configure the function keys by selecting PC Manager> Settings > System settings > Hotkey priority.
Perform the same steps to change to Hotkey priority in PC Manager.
Check whether your computer has hotkey drivers. To install hotkey drivers, search for your computer model in the official Honor website https://www.honor.com/global/support/. Download and install the hotkey driver.