You can reduce your home LV as long as it’s unmounted. (please keep in mind that shrinking has some risks )
Go like this:
umount /dev/mapper/centos-home
lvreduce -L 200G /dev/mapper/centos-home
Mount back your home partition as you’re done with it.
Then just extend your root volume.
lvextend -t -r -l+100%FREE /dev/mapper/centos-root
-t is test, if it’s ok just run the command a second time without -t