itself vs in itself

Question

1. Boldness in itself is no guarantee of success.
2. Boldness itself is no guarantee of success.

Firstly, I wrote a sentence (1), but then I wondered if the sentence also works without "in", as (2), because the reflexive pronoun itself emphasizes the idea of "without anything else added"

EDIT:

Two follow-up questions, are they able to occur at the positions?

1a. Boldness is no guarantee of success in itself.
2a. Boldness is no guarantee of success itself.

This "by itself for itself in itself" stuff kind of drives me crazy.

Answer 1

Yes, both sentences are correct, but "in itself" carries a particular meaning (similar to "per se", if you're familiar with that expression) that seems to work better in this context.

Yes, you can move either phrase ("itself" or "in itself") to the end of the sentence. However, doing so introduces some ambiguity: While "itself" or "in itself" can still modify "boldness", it can also modify "success". Therefore, I'd stick with the original word order.

Answer 2

Both work. "in itself" conveys a bit more emphasis and is a common stylistic choice. You are correct in observing that the reflexive pronoun is enough to convey the idea.