Yes you can freeze sauerkraut after the sauerkraut has been cooked and it will be just fine.
However if you do freeze the sauerkraut after you cook it then it will kill off beneficial bacteria.
When you make homemade sauerkraut you don't actually cook it but instead you ferment the sauerkraut when making it.
I sometimes ferment lots of sauerkraut and share some with my friends and neighbors and then I freeze the rest of the sauerkraut and it lasts for up to a year and sometimes longer.
Although it's best to eat the sauerkraut within 2 months to get the best taste and freshness of it.
But the sauerkraut will remain good and safe to eat for a year or longer but it just doesn't taste as good.