I guess folks in here are ignoring the old men/Russian POWs Ukraine has been capturing? I'd post the videos but it would likely get taken down but all you gotta do is search and you'll find Russia has been using a lot of "aging" men for frontline duty.
One the thing I've noticed Western Think-tanks/Ukraine/MSM never consider is that the Russian military is applying the Svechin long term strategy of attritional war, which influenced Gerasimov's doctrine. Albeit Zaluzny (Ukrainian chief of General Staff) did acknowledge that Putin/Russian General Staff were performing the 2nd Chechen war on them writ large in western press. The Russian general staff chief admitted after the war they focused on exterminating all combat capable people in that war in order to win the peace.
I have read enough of Svechin's book to see it play out in the Ukraine. To summarize, Svechin advocates a total defeat of the enemy with political and economic means far more important than military. Svechin was ideologically opposed to the "Deep Battle/Blitzkrieg/short war" men of the Soviet military cliches.
He advocates fighting a 'poor man's war (eg. we can see this with PMC Wagner, Separatists, Storm Z etc.) and a permanent defense, inter-cut by strategic offensives when enough force is being built up.
In the end the enemy is to be weakened in sequences until the final decisive battle against a completely exhausted enemy like Germany in 1945.
This is exactly what Russia has been doing since late 2022 after they expended their strategic offensive forces. Now in 2023 they claim to have recruited 410,000+ new personnel and raised 2 new combined arms armies, new corps hq and countless sub-formations. The MIC is claiming giant numbers (who knows if it is true?) but ultimately they are not using their resources in Ukraine.
The way the West media is talking about Ukraine is as if the whole Russian military is 'all-in' to Ukraine and it is a statemate. The pentagon John Kirby claim this which is completely the opposite of what the Russian MSM/telegram is saying.