TBH Ive found a lot of the creaks and groans come from stuff within the car i.e. things stuffed into the pockets, under the armrest, glovebox, boot etc.
Our 2013 IS300h doesn't have any creaks really. My son's 2015 Merc C class has 1 or 2 noticeable on rough tarmac.
Our 2016 RX has squeaky rear suspension, but thats been a longstanding thing with the RX since Gen 2, doesn't bother me much really. It occurred in the 3rd gen RX too. The 2016 RX is definitely more solid than the older 2009-15 RXs though