Russian and allied forces in total seem to have lost 2000 KIA and 6500 WIA. A total of about 8500 casualties. This amounts to about 4% of pre-war strength.

For Ukraine, the losses are far greater. Russian MoD estimates 14,000 dead and 16,000 seriously wounded with as many as 2000 others made POWs. This amounts to about 11% of pre-war strength.

A four times casualty ratio for Ukraine is believable considering that the Russians have air and artillery superiority. They've launched as many as 1200 land-attack missiles since the start of the war.

I wouldn't trust these numbers too much. As you say air superiority has been limited or pushed into a more restricted role and Ukrainian counter artillery has had at least some effect. Between the relatively slow advances against fortified areas and things like the atrophied/abandoned encirclement of Kiev I'm not inclined to think Russia has anything like a 4:1 ratio. Assaults into fortified areas (which is where a lot of the offensives have been stalling) don't produce those kinds of ratios unless you have massive superiority in equipment (doesn't seem so) and overwhelming concentration of forces (Russia had fewer men total and somewhat of an advantage in trained soldiers at the start). The Russians keep putting out bullshit about their progress in fortified/urban areas although it appears Mariupol is indeed close to falling.

There's tons of propaganda in the West about the Russian army "falling apart" which clearly isn't true but I'm not buying Russias MoD numbers either

Azov took extreme casualties in the last two days and now effectively ceases to exist as a single unit.

Azov has more men outside of Mariupol, definitely some elements in Kharkiv and probably Kiev too where they have training and recruitment centers in both cities. They seem to have lost significant forces in Mariupol (along with other elements of the Ukrainian army that formed the bulk of the defenders) but it's not clear exactly what kind of shape they're in.