It has one[1] (optional). Proxmox has a shittier, but more featureful, web UI.

[1]: https://blog.simos.info/how-to-install-and-setup-the-incus-w...

i like the proxmox web ui.

also, looking at the link you posted, it looks like incus can only do like a fraction of what proxmox can do. is that the case or is that web ui a limiting factor?