My sympathies are with Ukraine, and Putin's second invasion of Ukraine is not the only reason. That said, IMO, neither Russia nor Ukraine are winning.
In some areas, Russia is gaining a few 10s square kilometers, but taking months and 10s of thousands of casualties to do so. Russia outnumbers Ukraine, but the Russian losses to Ukrainian losses ratio is greater than the ratio by which Russians outnumber Ukrainians.
gab13by13's item 3 is basically correct.
Russia is wasting munitions - missiles, guided glide bombs, and drones - attacking civilians (hospitals, schools, and apartment buildings), evidently hoping to break morale. Hitler tried the same strategy with the Blitz.
Meanwhile,
gab13by13's item 2 is massively correct. Ukraine has shut down 35%-40% of Russia's refinery capacity, and has hit many refineries multiple times, each repeat being after Russia has started to do repairs. The repeated attacks mean not only that the reattacked refinery stays offline, but that man-weeks of repair time and replacement parts and structures are destroyed, possibly with specialist casualties. This months-long effort has caused serious fuel shortages - for the military as well as the civilian economy that literally and metaphorically feeds the military. Ukraine isn't wasting its munitions and drones, and is using those against important military and dual-use targets.
At ~2:10, this ~2 week old ~3 1/2 minute video has an icon matrix showing Russia's largest refineries, and how many Ukraine has hit,
https://www.youtube.com/watch?v=mGq2FFKCiWA . Basically, the few large ones that have not been hit are far from Ukraine.
Ukrainian drone have also driven Russia's Black Sea Fleet out of Crimea, except for coastal patrol boats, with major ships that aren't sunk or in drydocks outside of Crimea having fled/relocated to Novorosiysk. In addition to sinking and damaging Black Sea Fleet ships, Ukraine has also been carrying out an ongoing drone campaign against Russian SAM systems of all types, making Russia's anti-drone defenses quite porous. Ukraine isn't wasting its munitions and drones, and is using those against important military and dual-use targets.
It almost feels weird, finding something geopolitics about which a DU-member and I agree, but Russia is not winning in its attempt to conquer Ukraine.
Nor, however is Ukraine winning. Devastating Russia's military has not, yet, reclaimed all Ukrainian territory occupied by Russia.