people who support Russia/Stalin/China regimes.

Congratulations: That, and only that, is a tankie. It is a good practical defintion for the term.

Are tankies people who are economically left but socially and politically right

As I see it, tankies are just the same as the Trumpers. You can't really say where they stand socially and politically, because they do not have a coherent opinion or ideology. Everyone who opposes their favorite regime is WRONG, and everything their favorite regime does is RIGHT. Bonus points for every action and opinion that hurts "woke lefties", because the favorite regimes of tankies are all inevitably incompatible with progressive ideas and ideologies.

without knowing anything about the corrupt oligarchies in Russia or CCP China?

Imagine the answer a Trumper would give when you ask them if they don't know about Trump's corruption and character. The tankies answer just the same in response to allegations in regard to corruption and character of their favorite regimes:

First of all, none of that is true, because the woke lefties, the media, and everyone are all corrupt, and lying. And what is true, is all a well played move of brilliant 5D chess which will save us all, because the supposed "corruption" is actually all part of a very smart and deliberate system of ploys and strategems which the woke lefties just don't understand.

Now, do the tankies and Trumpers truly believe that? Who knows. Doesn't really matter anyway. What is clear is that both of those "ideologies" are dumb idiots.