If the goal is to avoid relying on a PC for the long term (e.g., installing custom ROMs later), there is a method that requires a PC to unlock the device. This is the closest achievable solution to the user's request.

Unlocking the bootloader on your ASUS ZenFone Max Pro M1 Go to product viewer dialog for this item.

Press Enter. The terminal should return a success message like "OKAY" or "Finished."

Locate the downloaded APK in your file manager and install it. Open the application once finished.

Open > Security > and enable Unknown Sources (or "Install Unknown Apps" for newer Android versions). Go to Settings > About Phone > Software Information .

Method 2: The Two-Phone Fastboot Method (Using a Second Android Phone)