Liquid Glass seems to be a source of complication for a not such important thing. I could see a lightweight version of Tahoe / OCLP, without Liquid Glass but allowing people to enjoy the rest of the new features.Progress has been shown earlier in this very thread too, me first by permission of Edu and later Edu themself.
There's a lot to be done like for example you can reach full acceleration as a proof of concept to show and this milestone was reached but it still doesn't end there, if many apps or UI elements are still glitching then it's not gonna be very usable even if you have a shiny translucency in your Dock. It's the minor details that take a lot of time.