Need help to find the right size (short legs)

Hi folks,

I really want to order a Canyon Aeroad CF SLX 8 this summer while they are in stock, but I'm unsure about the sizing.

I'm 181 cm with 80,5 cm inseam (short leg king, apparantly lol). This puts me at a size S, according to Canyon.

I've tried an size S before, and I am confident this ia the right size for me. What I'm worried about is if the standard stem length (90 mm) would be too short for my upper body. Should I get a longer stem instead? 100, or 110 mm?

I understand changing this later on will be a lot of hazzle, so hoping to get this right from the start.

The local bike fitter is unavailable until August, and I'm worried canyon will go out of stock before I get a proper fitting.

Also, I plan on getting the Canyon Gear GROOVE Aero extension (plz no hate, I don't have physical nor financial room for multiple bikes), in case that's relevant information.

Any tips are apprieciated!