is possible to get a 100% straight columella ?

No plastic surgery of the nose will produce 100% results. You may possibly be able to achieve a "straighter" columella or nostrils, but you'll likely still have some asymmetry. If you haven't already, then speak with a rhinoplasty surgeon to review options for you.Best,Dr. Chaboki

Improvement should be the goal in regards to something like this.   Find a board certified plastic surgeon who performs hundreds
of rhinoplasties and rhinoplasty revisions each year. Then look at the
plastic surgeon's website before and after photo galleries to get a
sense of who can deliver the results. Kenneth Hughes, MD Los Angeles, CA

The columella can be straightened but the cause of the crooked appearance must be identified.  Usually a graft can be placed in the columella to help straighten and support the columella.  You should see a rhinoplasty for consultation to see if you're a good candidate for surgery.

A columellar plasty can be performed to straighten a crooked columella or reduce a  hanging columella when present.

Your columella can probably be straightened but there is nothing about the human body that is 100%. Despite fantasies there is no such thing as a perfect body.