Not OP, but I use sunshine and moonlight for streaming my pc to various devices. Wayland forces me to use kms and I can't turn the monitors off while I'm doing it. Someone was working on a pipewire backend, so hopefully that goes somewhere.
GreenWithEnvy is also a nuisance on Wayland while Nvidia Settings Panel doesn't even work. I have a custom script just to control my fans on Wayland, but I'm eventually switching from Nvidia anyways, so it won't matter for much longer.
The primary maintainer stepped down, but there has still been work done by other contributors. The primary problem is that the underlying library is reliant on x11. This is the same reason why nvidia-settings doesn't have all of its features on wayland. Basically if nvidia's on tool doesn't work then there is no way that green with envy can either. There is an open merge request attempting to switch to a different library that Nvidia says they plan to move to eventually, but it is slow going.