Initially, the Russians were the aggressors, but now they are mostly in defensive positions holding on to the territory it has seized. The Ukrainian counteroffensive has been a huge disaster. They have suffered massive losses. It is one of the reasons for the schism between Zelensky and his generals. The counteroffensive was motivated by political reasons rather than military objectives. The US/NATO wanted a military victory to buttress flagging support for the war.
The 3 to 1 calculations are problematic. The largely conscript, untrained Ukrainian forces are no match for the Russian military. There are plenty of examples where the attacking forces suffered less casualties than the defenders, e.g., the attacking US forces against the Japanese in WWII.
i estimate current Ukr KIA at around 125,000. and of course, russian at 3x that.
125,000 would be horrific. The US lost around 500,000 in WWII. Based on population, the US is 8 times the size of Ukraine, the 125,000 would translate into a million deaths.
No way Russian KIAs are 375,000. In February 2023, launching the 2023 Military Balance, the IISS estimated Russian Ground Forces numbers had climbed to an estimated 550,000, including an estimated 100,000 conscripts and up to 300,000 mobilized personnel. This number should be set against the Central Intelligence Agency's estimate of 300,000 active duty before February 2022.