Ukraine

Is it safe to assume the vast majority of Russian soldiers are males between 19-30?

If so, based on the population breakdown that I looked up, Russias casualties are just under 10% of their entire population in that demographic in the first year of this conflict.

Based on so many videos I've seen and reports on Telegram, it's really old men.

I'm talking 45 to 65. I don't know the breakdown but it's A LOT of older men.
I think that's the vast majority of contracted soldier.

Russia has a law agaisnt sending young (conscripted) soldiers into battle ( after Afghanistan )

There is a Telegram channel that reports on Russian death notices and it's a whole bunch of older men.