Very interesting as usual. You ask a lot of interesting questions but sadly my time is limited. I'll just respond to a couple of points.

From what I read, both Kyiv at first, and now Kharkov ongoing, are fixing operations to keep Ukrainian forces out of the Donbas. Personally, I think Russia hoped Kyiv would capitulate because they sent nowhere near enough forces to take/hold the city. That was a fail. But they sent enough troops to keep a lot of Ukrainian forces tied up there for weeks.

Russia advances and retreats around Kharkov, much closer to the Donbas. There Russia again fixes a lot of Ukrainian troops around Ukraine's 2nd largest city.

This is not and will not be trench warfare a la WWI.

The area just outside the Donbas (west and south) was built up over the last years like the Maginot line after WWI. Lines of hardened positions at depth. Let's call it "The Donbas Line" or DBL. The Russians can't go around the DBL as the Germans did through the Benelux, because the DBL is long and the land is secondary. The Russians primarily want to capture or kill the main Ukrainian forces in the DBL. If they do that, the war will turn decidedly in Russia's favor.

Based on the same Liveuamap you are looking at, but obviously reading different sources, the situation doesn't look good right now for Ukraine. Looking at drone footage, Russia has destroyed multiple layers of the DBL. Russian salients to surround about 15k Ukrainians in/near Lysychansk are about to give them (some reports say already have given them) fire control on the exit from that area. In the last days, Russian advances have quickened as the hardened lines of the DBL have been destroyed.

Credible reports of several hundred soldiers surrendering after the Mariupol surrender of about 2000 support my theory that Russia is close to another major victory. Mariupol was a very important psychological victory for Russia.

We'll see in a couple of weeks if I'm right.