Do you mean LXD and Incus? If so, sort of. Incus is a fork of LXD but it diverged quite a bit and due to the LXD licensing change, Incus can't take anything from LXD but LXD can from Incus. Incus is a community project and is a lot more active. They both use LXC under the hood.

Finding a simple GUI is not going to be easy because everyone has a different definition of what "simple" means. It also depends on what you mean by "review" and "manage". There were a few web UIs for LXD containers and they were ported or used for Incus containers. Some are still maintained and active.

I personally prefer the command line and find it easier and simpler than using graphical interfaces so don't have a recommendation. When the number of containers and servers becomes large enough to warrant anything else, then that's when automation starts.

Mostly I want a quick glance at the state. I don't really do much using cockpit. It is read only for me and I'm using command line to do anything. I like that cockpit is generally mobile friendly because I can use it remotely as all my machines are on tailscale/headscale.