Some updates, once I had the opportunity to go to a bikefitter and test some bikes.
Apparently, there is no substitute for a test ride. I've tested bikes from size 51 up to size 56 and there is low correlation between size and feeling comfortable on the bike.
Some impressions:
Orbea Avant size 53: stack is ok but reach is too short. Would need longer stem. Standover height and minimum seat post height are okay.
Trek Domane 56: reach is okay, stack is too high for my taste. Standover height is okay, but minimum seat post is not. Would probably need a shorter seat post (and lose some compliance) and play with spacers/stem angle.
BMC Roadmachine 51: Reach is almost ok but stack is too low. Standover height is okay and also minimum seat height. Would work with a flipped, longer stem.
BMC Roadmachine 54: Reach is almost the same as the 51 and stack is just right. Standover height is too high, though. Also issues with minimum seatpost height.
Rose Reveal 53: Reach is a bit on the short side but is almost there. Stack is perfect. Standover height is okay and seat height is a few millimeters away from ideal. Would work with a longer stem and shorter cranks.
So, after testing some bikes, I still haven't decided. But it is clear to me that due to my challenging proportions, I should never buy a bike without a test ride.