> Leninism (and it's descendants) have a totalitarian state system (socialist, including non-Leninist Marxist Communist, critics tend to call it “state capitalism”)
_Lenin_ called it "state capitalism." That was the official policy of the USSR under Lenin. State capitalism.
Lenin called a transitional phase that was intended to take 6 months to establish and another 6 months to phase out into socialism “state capitalism” (it may be the case that “war communism" of 1918-1921 was officially recognized as something of an extension of that phase necessitated by emergency), but state capitalism was never officially the long-term policy or the self-description of the state of the economy past that point; the criticism from non-Leninist Marxists is that what the steady state of what the USSR became was state capitalism, not socialism.
The NEP wasn't (in its own theory) state capitalism but a transition from war communism (which I think was, even in its own theory, still state capitalism) but to a mix of “socialized” industry and state-guided private capitalism. (Yes , critics would say that the “socialized” industries were really state capitalist and that the degree of centralized “guidance” made the private sector also state capitalism, but we’re talking about what Lenin and the internal theory of the USSR portrayed it as, where it was a different temporary stepping stone to fully socialized industry.)
> The NEP wasn't (in its own theory) state capitalism
That's not what wikipedia says. I can't argue as I am no expert in such matters myself having read almost none of the primary material (but I did read "The Tax In Kind"... which I was assuming outlined the theory of the NEP).
Wikipedia on NEP:
Lenin considered the NEP as a strategic retreat from socialism. He believed it was capitalism, but justified it by insisting that it was a different type of capitalism, "state capitalism", the last stage of capitalism before socialism evolved.[15]
_Lenin_ called it "state capitalism." That was the official policy of the USSR under Lenin. State capitalism.