Electronic & Hydraulic Shifting (Di2, Ui2, customisations)

Unless you find someone who has done it on your exact setup then you will probably have to bite the bullet and try. Smaller front chainrings is the obvious (but not always cheap solution).

Capacity can be taken with a pinch of salt though. I set up a Shimano mechanical 10s 4700 50/34 with an 11-40 cassette using a road link. Works fine and is 4T more than the stated capacity for the mech.

FYI capacity if different from max teeth on the rear cog. Capacity is the total range it can cover - this says the wifli rear mech has a capacity of 37, so with a 50/34 you could run an 11-32 but potentially a little bigger. With a 46-34 you could run a 11-36 (with a road link).