I have very little to add to your assessment, Ewan, and it was good to read opinions based on what the RC is, which is an eminently driveable and pleasing car in its various modes, rather than what it isn’t, which is a car designed to stretch everyday practicalities. I always switch to SPORT mode when outside of towns, and SPORT+ for fast roads and motorways. Have you tried CUSTOM settings?
I share most of your quality niggles, though the 2019 facelift was an improvement over the 2016 version in several features. I personally find the auto high-beam more than adequate, but then again, I’ve not had it on other cars and therefore have no points of comparison. As regards the seat heating, I would recommend keeping it on the maximum 3-led setting if you feel the need and are driving for any length of time. The heating effect seems to be more cumulative than immediate, and although the system is therefore pretty useless for short drives, I find it acceptable for longer ones.