The free upgrade offers from Microsoft officially ended in 2016.
The free upgrade offers from Windows 7 and 8 to Windows 10 and 11, which allowed using older product keys for activation, officially ended on September 20, 2023.
Back up all your data.
Visit:
https://www.microsoft.com/en-us/software-download/windows10
Download the Windows 10 Media Creation Tool to make a bootable USB drive.
Go for a Clean install.