with maxroot you cannot increase the root volume. this defines the maximum size of the root partition. as the calculate size is lower (as you only have a 250 GB) it does not increase to 200.
in order to get what you want, do the following:
Code:
linux maxvz=26 swapsize=24
you will still not get a root volume with 200 GB, but you can extend the root volume with LVM standard toolset as you have about 137 GB free space in your VG pve.