fstab – Block device management

I searched for this in the forums, and did not find anything that could help me, if this was already discussed please forgive me.
So I have 2 problems/questions:

  1. I recently installed unbuntu server 20.04 and customized the volume group and lv’s, and when I do a simple “df -hP”, I am puzzled to find that one block is shown by ID, and all others by name:

root@ubuntutemplate:~# df -hP |grep -E “home|usr|var”
/dev/disk/by-id/dm-uuid-LVM-ejH0HN7VfcuXORf4DjdZGWAPK7mM9p2sDcc0AYNUXBSZd3CWB227AeKHoDapbRPA
5.0G 2.2G 2.9G 43% /usr
/dev/mapper/vg_ubuntu-lv_home 5.0G 68M 5.0G 2% /home
/dev/mapper/vg_ubuntu-lv_var 8.0G 1.3G 6.8G 16% /var

As you can see usr filesystem is mounted by id and all others by name. Fstab is configured the same way for all the filesystems.
What controls this behavior and how can I make it same for all?

  1. I renamed volume group “ubuntu–vg” to another “vg_ubuntu”

Noticed that udev rules are still referring to old vg name (I already updated grub and initramfs)
example:

root@ubuntutemplate:/etc/udev/rules.d# ll ubuntu–vg-lv_var.rules
-rw-r–r– 1 root root 140 Feb 17 11:46 ubuntu–vg-lv_var.rules
root@ubuntutemplate:/etc/udev/rules.d# cat ubuntu–vg-lv_var.rules
# Written by curtin
SUBSYSTEM==”block”, ACTION==”add|change”, ENV{DM_NAME}==”ubuntu–vg-lv_var”, SYMLINK+=”disk/by->dname/ubuntu–vg-lv_var”

Is this problematic? Everytime I decide to change a vg is this going to happen? Is there anyway to
automatically update all rules for all block devices (lvs)? Shall I change it by hand?
Thank you very much for the support in this

Cheers