Hi Magic Man1,
I am Dave, I will help you with this.
If Windows cam pre-installed on your Asus Strix G15 2021, then you can re-install Windows anytime and it will activate automatically, because the OEM licence is stored on the motherboard.
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', and activation will not be an issue