Think your device have to be in fast boot mode by holding vol down and power button together until it resets to the mode.
no need to be in fastboot mode, i did so many times uninstall and reinstall back when phone in power on mode. since you can bring up the XiaomiADBFastbootTools meaning you have the correct Java SDK install so that remove from the equation. ADB tools install ? enable developer option and on the USB debugging mode is probably the next check you can do. if those are done try this
1. made sure the usb cable can do data transfer and not just power charging else won't work. you will know when there is option pop up asking you file transfer or charging only.
2. brings up the XiaomiADBFastbootTools then connect using a data transfer usb cable from the pc to your phone with usb debugging mode enable
3. if #2 can't, connect up the pc and phone first then bring up the XiaomiADBFastbootTools
if all 3 still can't i also don't know what to do haha
btw debloat is just to remove those list from your phone as it is not physically remove the apk so won't free up storage space. to physically remove the apk to recover some storage space you need the other method. one thing about debloat is if later on, you find that you need that feature, you can reinstall back via the XiaomiADBFastbootTools