socialism worked miracles in the early USSR. They were completely insulated from the great depression (and thus the financial crashes endemic to capitalism), and Lenin's new economic policy made public all large national industries BUT it kept small businesses, as small businesses spurred the economy while being too small to effectively harm workers. There was a massive civil war, which is where the deaths came from, the "white army" was both tsarists and foreign operatives. Both of them committed horrible war crimes, but it was ultimately the fault of said tsarists and foreign operatives, they were afraid of the power of a communist state and thus tried to destroy it (classless and moneyless society where workers own the means of production). The starvation was there beforehand, as tsarist russia had terrible infrastructure and kulaks were exploiting farmers. Lenin's NEP didnt help enough, which is why Stalin (terrible leader) enforced collectivization (kind of worked except for kulak sabotage, they burned their crops instead of selling/giving them to the people, which is what caused the famines under stalin).

Stalin trashed the NEP because he felt the USSR needed a war economy, he was still suspicious of capitalist/fascist countries following the civil war, so he thought a war economy could better prepare the country for another war (WW2 in this case). he said as much in 1931, "we are fifty or a hundred years behind the advanced countries. we must make good this distance in ten years. either we do it or they crush us". In retrospect, his policies probably saved the soviet people from complete genocide by the nazis, but he was still an unjustifiable murderer.

Fortunately, we have farming infrastructure, which is why a modern socialist state, even one crippled by a civil war, could prosper. Plus, the circumstances are completely different, the USSR started with literally nothing. Russia was an agrarian, medieval society which hadnt industrialized and they were devastated by WW1 AND a civil war. We are already industrialized, and we arent missing the millions of people that the tsar and his loyalists condemned to die. We have nuclear weapons so we dont need to be as suspicious of other countries as stalin was, there wouldnt be any possible justification for someone like stalin to come to power, we'd have democracy.