I am not sure if this can be fixed during installation, as I am not very well versed in ansible/rocky/lvm.
I found that the root directory of the nodes is limited to 70GB in size in all nodes I deployed - two with 256GB drives and one with a 512GB drive - and the /home directory is given the majority of the disk space. As longhorn uses the root volume for PVCs this leaves the majority of the disk unusable by longhorn.
I was able to resolve this manually by running the following to recreate the volume for /home with a smaller size and granting the newly available disk space to the root volume.
#Install xfsdump and backup /home
yum -y install xfsdump
xfsdump -f /tmp/home.dump /home
#Unmount /home and remove the volume
umount /home
lvremove /dev/mapper/<vg name>-home
#Create a new volume for home, limited to 5GB, and restore the backup to it
lvcreate -L 5G -n home <vg name>
mkfs.xfs /dev/mapper/<vg name>-home
mount -a
xfsrestore -f /tmp/home.dump /home
#Extend the root volume to use the newly available space
lvextend -l +100%FREE /dev/<vg name>/root
xfs_growfs /dev/mapper/<vg name>-root