Is there a new GUI for LVM

You can install KVPM, but you have to install some KDE dependencies it has; they're not many as they said in their page. If you use some QT software it is very probable you already have the dependencies already on the system.

sudo apt-get install kvpm

system-config-lvm is outdated and can't manage some new features of LVM (as reported by itself) so don't bother trying to install it.

You can use KDE Partition Manager

sudo apt install partitionmanager

At the moment it does not work under Gnome Wayland session. So you have to use either X11 or Plasma Wayland. In the near future, KDE Partition Manager will be able to run without using root privileges (I already have most of the functionality working), then it will work much better under Wayland.

You can also allow running XWayland root GUI apps if you first run "xhost +".

EDIT: Ubuntu 20.04 has KDE Partition 4.0 which works well on Wayland.

Blivet-gui is a graphical tool for storage management that uses Blivet library

https://github.com/storaged-project/blivet-gui