Cube AERIUM C:68X SLX // Size recommendation // Road bike + clip ons vs TT stack / reach confusion

Hello together,

I am currently looking to by my first TT bike coming from a road bike with clip on bars and very interested in the new Cube Aerium (for which I could not find a “Bike Fit Assistance” thread) and am looking for assitance in choosing the right size.
When comparing the X and Y numbers from my current fit to the geometry values of the Aerium I am a bit confused, as my own pad stack looks quite high, while my pad reach looks rather short and I am not sure if I am measuring something wrong or if the difference is just that large.
My current bike is a Stevens Arcalis Gen1 size 58 with a changed stem (+20mm), handlebars (38mm) and the Redshift aero bars, with the following fit:
Height: 186,5cm
Inseam: 88,5cm
Arm pad reach (middle as Cube measures to the middle): 470mm
Arm pad reach from saddle (to middle): 555mm
Arm pad stack: 690mm

Attached you find the geometry data from my current Arcalis and the Aerium, as well as video of my current position.
https://drive.google.com/file/d/1R0DlEHawgLcpR6naMxzs2H4H79-CPdlp/view?usp=sharing

I was also looking at a Speed Concept, but the not so narrow cockpit seems like a dealbreaker to me.
Any help regarding a suitable size would be greatly appreciated.

Thanks and kind regards,
Christopher
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