So from my understanding is that this ship is a Separatist ship. But beyond that we aren't given any real details about why the ship crashed or what its purpose was. At the moment it's a plot device that hasn't been explored much further.
I believe the best purpose/background right now for the ship is that it was a way to create a very rough timeline of his youth using information a mixture of information that is already known (The Clone Wars and Separatist Movement) and information given in Andor (When he born & Adopted by Maarva)
- Andor is Born in 33 BBY
- Andor is Adopted at Age 9 by Maarva Andor (~24 BBY)
- The Clone Wars Begin 22 BBY
Outside of this, we really do not know much in terms of the background of the ship, the gas onboard, or what happened to the other natives of Kenari (and how this may relate to Andor's past in a Separatist Insurrection Cell on Ferrix or his future travels looking for people).