Russia has used this tactic before with success. They used to send wave upon wave towards the Germans. Your choice was get shot by Russians or maybe get shot by Germans. Turns people choose to try and kill the Germans first.
As far as I know, they were fighting a rather well trained army which had better training and weapons than they did.
It's realistically possible that they could just win the war just by sending so many people that Ukraine runs out of people to fight back even if they were killing multiple Russians per Ukrainian that died.
It's like everyone forgot the reason Russia were feared wasn't that they were a super power, had an amazing military. It was the fact, they don't care how many Russians die to win and they are brutal.
China is making serious overtures about invading Tawain. It's well known they want to take Tawain "back". Letting them US and other countries waste their weapons on killing Russians is benefical to them. It also creates an overall unstable geopolitical envoirnment which they can take advantage of. The enemy of my enemy is my friend.
It is much better off continuing to do what they're doing today: providing token diplomatic support to Russia in exchange for steeply discounted fossil fuels.
No, if we're talking about Germans attacking during a world war, it was an existential threat to Russia. The same cannot be said of Ukraine.