Ukrainian sources claim "30,000" troops with approx. 14 brigades/equivalents trapped in the pocket or contesting the outskirts.
Russian sources claim approx. 40 Ukranian infantry battalions (full strength: 20,000 infantry- it is likely that real strength is far less than this due to losses ) involved in the battle.
So both sides have similar claims on how many ukr units are in there.
The extremely drawn-out conduct of this battle by the Russian command is similar to Bakhmut.
However, instead of using PMC convict troops they are relying more on firepower superiority- artillery and airstrikes- and drone superiority to wear down the Ukrainian forces meter by meter.
Marinka city has finally fallen to the Russians, with only a few streets left in Ukrainian hands. Pretty much the same units on both sides have been engaged in positional fighting in these ruins, with neither side making a serious effort to take the whole city in 2023.
In the past couple of weeks the Russians have executed local counterattacks and erased most of the minor gains the Ukrainians accumulated over 4 months of attacking in Eastern Ukraine. All that's left in in the south there are still two small bulges in front of the 1st line of defense that haven't been fully retaken yet. The Ukrainians keep on launching harassment crossings over the dnepr with miniscule forces that have to be cleaned up over and over again.
I believe that the extremely drawn out conduct by the Russians on all fronts and the lack of attacking is intentionally done to present an image of a "stalemate" in Ukraine meanwhile in reality the Russians have strategic initiative. They know that as long as the Western public believes that it is a stalemate, fewer investment in Ukrainian aid will happen over time. And they have been right with this approach.