Is Strawman fallacy same as misunderstanding?

If a person misunderstood a topic like atomic structure and thought that it is proton that orbits an atom and he used that in his argument would that be considered Strawman fallacy?

No, that'd be a lack of domain-specific knowledge rather than a fallacy.

The argument itself, by the way, COULD be fallacious on its own, but that has little to do with the truth of the premises supplied.

It doesn't seem to be a fallacy as much as an argument with a false premise.

It is my understanding that Strawman is a very specific fallacy where a person is trying to misinform someone who does not have a firm understanding of said person's opponent's argument. The most common place you'll see Strawman is in partisan news sources, where the opposition's actual ideology is always distorted in some way in order to further justify the ridicule.

The internet treats Strawman as a generic Fallacy Fallacy in which a person will simply claim someone is committing a Strawman fallacy to get out of defending their argument. Especially if someone tries to attack the form of an argument, in the same way that Socrates defended himself by asserting his prosecutor's claim that he was corrupting the youth that the entire village was trying to raise (one bad apple spoils the barrel) followed the form of one corrupts, many help... then revealed that form to be false with the dissertation that a horse one good trainer and many inexperienced trainers (the village) is unlikely to get trained (many corrupt, one helps).

This is not a Strawman, it's an attack on the argument's form. The way people are meant to argue. If I misunderstand your argument it is your burden of proof to explain it to me, simply asserting I am strawmanning your argument does absolutely nothing to defend your position. Similarly, it is impossible to perform a strawman attack (which is meant to misinform some third party) when debating with someone who is actually well versed in the opposing argument.