^^^^^^
The trim position is like a "half click" between a full shift. It is important to reset the shifter to the true "0" starting position and any inline adjusters reset to their most retracted position and the derailleur set to the proper small ring position by way of low limit stop (the "L" screw) before attaching the cable. From there the inline adjustors can be used to account for any seating of the cables and tension lost through the course of use.

Different quality tiers of shifters will have varying configurations of trim options. With a 2x, the options can be as many as: Low, low trim, high trim, high. Anyway, this feature probably explains the extra clicks in your shifter.

It is rare for there to never, ever be any rub. Especially when cross-chained with short chain stays and big cogs. But it is the ideal and is most often achievable or at the very least rendered inconsequential with enough attention to detail.

You shouldn't really cross-chain anyway. So the trim is intended to be an in the moment temporary fix until a better combination of gears that provide the same ratio can be found.