According to their Github, it hasn't progressed much since 2020-2021[1]. Apparently, there is still a Gala issue and bugs related to Plank Dock/Wingpanel holding it back[2]. There's also a proposal for a Wayland Dock for Elementary OS 7[3] that doesn't seem to have advanced much.

It seems like it was scheduled to be released by version 7, but priorities have changed. Let's hope they can polish it for 8.

[1] https://github.com/orgs/elementary/projects/12

[2] https://github.com/elementary/gala/wiki/Experimenting-with-W...

[3] https://github.com/orgs/elementary/projects/99