

There are multiple way to de this. The easiest solution would be to une a second disk with same size or bigger and clone the current one onto the new one, using dd or clonezilla
if you have enough size on your dis_ for a second root partition, you can use dd to clone the existing root partition in the new one, edit /etc/fstab on the new one to point to the correct root partition, and us grub-mkconfig if you use grub, use grub-mkconfig to reconfigure it. It should automatically detect the new partition.
Being angry at the Mozilla foundation for those changes is understandable. Switching to Brave because of it is plain stupid.