If there is no such password for Firmware than why is it requesting for it in Administrator Password Login Reset Mode?

Please refer to this excerpt from If your Mac doesn't start up all the way - Apple Support:

"If your Mac is using a firmware password, the lock icon appears when you try to start up from another disk or volume, such as an external drive or macOS Recovery. Enter the firmware password to continue."

Unfortunately anyone with physical access to the Mac could have set a firmware password (especially anyone with access to an admin password). A firmware lock can be activated if FindMy triggers the laptop to become disabled. It is also possible that a bit flipped in the firmware which makes the Mac think a firmware lock is enabled. If you acquired the Mac from someone else, then it is likely the previous owner enabled the firmware lock. It really does not matter since @John Galt has already provided you with the only options to remove the firmware lock. If you don't know the firmware password, then you will need to take the Mac to an Apple Store or an Apple Authorized Service Provider along with valid proof of purchase and ID so Apple or the AASP can remove the firmware lock. Otherwise you will need to live with the crippled nature of the Mac and hope it continues to boot normally.