Extend /dev/mapper/system-root

I am new to SUSE, my /dev/mapper/system-root is used up. I tried to extend it with:
lvextend -L + 510G /dev/mapper/system-root
Afterward, I can see that system-root is now 570 G with lsblk:
# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 1.1T 0 disk
??sda1 8:1 0 1.1T 0 part
??system-root 254:0 0 570G 0 lvm /
??system-swap 254:1 0 2G 0 lvm [SWAP]

However, df still shows 60 GB, and I still get “disk full” message, How can I extend /dev/mapper/system-root ?
/usr/sap/HXE/HDB90> df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/system-root 60G 60G 0 100% /
/dev/mapper/system-root 60G 60G 0 100% /home

Thanks in advance!

Hi
Is lvextend all you did? If so have a read here: https://suse.com/c/linux-lvm-logical-volume-management/

What do you have running on this system? If it’s just a test system, for / it should be enough for the operating system if running btrfs?
Are you running btrfs and snapper? If so then have a read here: https://en.opensuse.org/SDB:BTRFS