Some people say they have seen photos of Territorial Defense travelling in unmarked cars, and the Ukrainians have released photos of a Russian ambulance full of weapons. So Russians are shooting up civilian cars which don't stop, and Ukrainians may start firing on Russian ambulances.
Edit: The Ukrainians claim to have destroyed 200 vehicles and a headquarters near Melitopol on the Dneipr, so even in the area close to Crimea, there are still large Ukrainian forces operating behind the columns.
I've seen lots of posts of people online suggesting different ideas of what Russia's strategic objectives in the war are, and I suspect they're all operating from the incorrect premise that Russia has a clear strategic objective at this point. I suspect to the extent that Russia has much of a strategic outlook it's just "how far can we push to maximise leverage and options in the inevitable negotiation stages"
I think that is why many Anglo military and think-tank commentators have overestimated Russia's chances. Their whole identities and careers are tied to the idea that through professional advice and the latest military equipment, any state can use a bureaucratic military to achieve rational policy objectives. But what do you do when the chief executive is totally out of touch with the facts on the ground, his subordinates are too scared to say so because they would have to explain why the army was in bad shape, and you need their permission to move towards objectives you can actually achieve? That was the US and UK situation in Afghanistan and Iraq for a long time, the military was not there to win just to avoid embarrassing the current government by losing. And from the government's point of view, making the concessions that would lead to achievable objectives were more embarrassing than keeping the war going.
Its possible that the Russians will break through somewhere before they run out of bodies and equipment, but I don't know what they would be able to achieve that would last even ten years.
Edit: A US DoD spokesperson says that the US has not seen any significant Russian forces outside the initial 190,000 troops entering Ukraine. So again, the invaders were outnumbered even before the Ukrainians started arming the people and calling up veterans of the Donbas War. They have more artillery, tanks, and aircraft but not more troops (and to take defended cities you need huge numbers of infantry).