Linkage?
My 2016 wasn't notchy, it was OK, but then I found it harder and harder to get it in gear. Turned out the rubbers at the gear linkage had perished (after only 20k, of which 18k of that is sitting in 6th on motorways!) and was causing huge slack and the gearbox was terrible. Wouldn't go in gear, false neturals, no feeling in slotting into gear.
Ended up removing the lot and using solid linkage connected to the original thread. No more rubber, no more slack.
Have a look at the linkage, see how much sideways play there is in it.