9th gen LT vs Premier - what is the difference?

Ok, now that I have your attention, let me elaborate on my question. I currently have an 8th Gen Limited LTZ which has pretty much all the nicest standard OEM GM bits from the parts bins (slightly stiffer suspension, larger diameter rims, etc.). I am trying to understand what GM has done with the 9th Gen Impalas in terms of trim levels.

My understanding is that in previous 9th Gen years, what is now called the Premier (2LZ package) was known as the LTZ. name change aside, is the Premier still a LTZ-esque Impala?

I know the Premier comes out of the starting gate with the 3.6 V6 and an overall nicer base package of accessories than the LT and definitely better than the LS. On the 9th Gen Impalas, what do you get on the Premier which is NOT somehow available on a loaded LT? Does the Premier have a stiffer suspension which is not available on the lesser trim levels? Is the transmission gearing more performance-oriented? Different steering ratios?

Hopefully you get where I am going with this. Thanks in advance for your constructive replies.