Restore chromebook from windows 10 (TGL) (ELEMI-motherboard)

I wanted to restore my hp i511th gen back to chromeOS i have the usb backup which was asked to be made while changing firmware because at the moment i really need audio and do not have a medium to pay for patron(sof driver) or buy a Bluetooth audio device. So can you guide me with step by step process of restoring chromeos and can i again come back to windows without affecting the health of my laptop because after my exams i would have the medium to pay for the patreon i would want windows again on this device

First of all, this process is in our documentation.

Second, Linux is free and doesn’t require reverting your device to stock.

Link to documentation: Reverting to Stock chromeOS | Chrultrabook Docs

can i use audio in linux without the paid drivers? and can i install kali instead of ubuntu

also please while installing kali it showed media device could not be mounted something
pls help

Why do you need to use Kali? Please actually read the list of supported distros on the docs.