So... I am struggling to see why the rebel player would ever pick something that wasn't the nav objective from the imperial player. I would love some thoughts on how/what/why nav objectives people are choosing for imps please

The reason I ask this here is that I see very few listed builds showing their objective choices, which seems like leaving a key piece of the puzzle you are approaching out of the solution. Hence I feel it's a list building subject, rather than a general one

If you use 2V list navigation objectives are your achilles heel. The only safe option seems to be minefields.

With Gladiators however, especially the ones with engine techs on board, you can succeed with any nav objective.