Russians are apparently digging into their positions, building trenches where they can't advance like in Kyiv.
I think Putin is attacking in the West, even ineffectively, to keep anyone else's troops from entering the country and holding the Western half of Ukraine, which could have been easily done weeks ago.
I also think Russia is desperate to make sure no one else helps Ukraine with men, thus the nuclear threats. What if Russia did launch a tactical nuke at, say, Australian troops that showed up to help? Worldwide condemnation? If so it would be worth it (if anything can be said to be worth the lives of soldiers), to turn China against them, it could end the war. I mean if tactical nukes are so clever why not use them against Ukraine? Talk about psychological warfare, it would surely be very effective at terrorising Ukrainians and getting them to flee.
I think the truth is he won't use them, unless someone invades Russia which is never happening.