1
You can create a bootable Windows 11 USB on an empty 8GB USB flash drive and use that to clean install Windows 11 on the new drive.
Click this link: https://www.microsoft.com/software-download/windows11
to download the Media Creation Tool (Click on Download Tool Now), with that you can create a bootable USB flash drive (min 8GB) using that tool.
Then, Boot your PC from the Installation Media you just created to begin installing Windows 11
During the installation process skip the steps which ask for a product key and select the option 'I am Reinstalling Windows 11 on this PC'.
2
For Windows activation, where did you get the Windows licence?
If Windows 10 or 11 was pre-installed on your laptop, then Windows should activate automatically from the OEM licence stored on the motherboard.
If Windows 10 or 11 was not pre-installed, where did you get your Windows licence, did you purchase a full retail Windows licence from Microsoft or from a 3rd party retailer?
Or is your Windows licence based on a previous Windows 7 or 8 licence?