Afaik they're waiting for version xx.1 with bug fixes. Idk if GNOME is unstable in xx.0 and idk why it has such a special place on Arch but what I do know is that Plasma 6 is quite bad now with its 6.0.2 so I guess this delay is a good idea because I'm a GNOME user and I want stable experience
It's already in extra-testing so I expect it to come soon, unless its dependency on util-linux-libs-2.40rc2, which is currently in core-testing, slows it down.