Mozilla has introduced a built-in dedicated backup tool designed specifically for users on Windows 10 and 11. This is the most seamless "download-free" option available today.
It allows you to select specific data to save, such as mail (for Thunderbird users), contacts, history, and cache. firefox backup tool download
It recommends saving the backup to a local folder or OneDrive for easy transfer to a new device. Mozilla has introduced a built-in dedicated backup tool