Recently I've started exploring the basics of Buddhism and I've got a question that bothers me a lot.

The purpose of every soul is to end the cycle of reincarnating and obtain nirvana through mediation or other means. If one accomplishes that and stops the eternal cycle of reincarnating, he becomes totally free. Overall, Buddha always tried to avoid the question of what nirvana truly was and rather wanted to help people to achieve it placing it as the main goal of every soul.

However, what if my ultimate goal isn't the immortality of my soul, but the immortality of my personality? What if the only thing I want is to be remembered for centuries and become a historical figure? What if I am not afraid of staying in the cycle?

It's similar to the case of, let's say, Alexander the Great. He was known as one of the most powerful kings in the world and he is still the matter of continuous study. His name is immortal, therefore.

I think you are confusing legend with eternity?

Your spirit and soul go on in eternity. Who you are/were goes on in legend.

I do not believe in reincarnation, but I guess that is not what you are asking.
I do believe there is a phenomena we call reincarnation but it is something entirely different than reincarnation.

You didn't get what I meant.

Some people spend their lives to achieve nirvana making it as their primary goal. But what if others don't need this freedom and instead they want their name to live forever?

To sum up all this, do we really need to free our souls?

Many people never do free their souls so I guess the answer is no.

For one if reincarnation and what you are asking is real then why is there so much crime wouldn't reincarnation evolved at least evolved us to the point there was no more killing?
So no I do not believe that ALL ever have their souls freed.

Crime appears to be the result of souls that never learn their mistakes and, tehrefore, never achieve nirvana.