Wheel size Question / Experience values

Hi there, I wanted to get some proper rims for my A4 Avant 2.5 TDI Quattro 8E and now I’m thinking about which size best fits! At the moment I have 235/45 R17, S-line sports suspension and even deeper. The whole thing is actually relatively comfortable and yet sporty. Now my question, has any of you had experiences with 235/40 R18 or alternatively 235/35 R19? But what do you say to the 35 cross-section? .. is it going to be too hard after all? From my side it can be hard but should not be too extreme is certainly not ideal for the rims I accept. In the 18s I have no doubts, however they hardly differ from the 17s in my opinion… 19s are hald after all nen tick “fatter” 🙂 Greeting, TT!