disk space before. lvm/vg only uses 48G of the available 98G:

# Increase the Physical Volume (pv) to max size
pvresize /dev/sda3

# Expand the Logical Volume (LV) to max size to match
lvresize -l +100%FREE /dev/mapper/ubuntu--vg-ubuntu--lv

# Expand the filesystem itself
resize2fs /dev/mapper/ubuntu--vg-ubuntu--lv

disk space after. lvm/vg makes 100% use of the available space