I’ve had recent experience of driving 3 Lexus cars - my own (of course) and two courtesy cars….a UX and an LBX. My own is an F Sport, and the other two were F Sport Designs. The ride quality on all 3 was exactly the same….fidgety, and not particularly great over rough or potholed ground. It’s a Lexus thing in my opinion, and the Aftersales manager at my Lexus dealer - who has extensive experience of the newer smaller Lexus models - agrees. It’s something you’ll probably need to get used to. I don’t think it helps they all ran on runflat tyres either….as yours probably does. How you deal with the runflats is up to you….there are options, all flagged up elsewhere on this forum🙂