Go to Ushuaia, and book a normal ship just like all other folks do. You will have 100x more rewarding experience from all of it, guaranteed. Its not just destination but whole road to it that make such trips worthwhile and you will keep remembering it for rest of your days.

Cruises are for folks, how to say it politely... who gave up on any form of adventure or excitement in their lives. Dont be that person, not yet at least.