i'm glad eric called me out on the canyon small vs xsmall topic, changing the armpad brackets is much, much easier than changing the bike!
the "shrug" that you are doing is very good and will - at first - only be sustainable for short periods of time (most likely). it is normal to only be constantly looking a few meters up the road, what most people do is they take occasional glances further up the road. i almost look "sideways" when i look far up the road. i don't really know how to articulate what i mean, but i'm basically saying my neck doesn't tilt far enough for me to look straight up, i kind of look up and tilt my head sideways. i'm not sure that will convey what i mean, but it's the best i got.
in training, you'll have to look up far more often than when you race, due to increased distractions. the BEST place to train head position and posture position CAN be on the trainer. especially with mirrors and/or video feedback.
interestingly - bjorn's point about the sternum is similar to what one should feel when swimming. this - when swimming - elevates your hips and legs for better body position.
Accelerate3 Coaching https://accelerate3.com/
Moxie Multisport https://www.themoxiemultisport.com/