Here 35e + 15e postage:
https://www.bike-discount.de/en/shimano-steps-sw-en600-l-switch-unit-left-22.2mm-2
I understand that the Bluetooth connection also allows you to adjust the offset of the hub gear, i.e. to ensure that the gears shift as smoothly as possible. In this model, you cannot make this adjustment manually by turning a screw.
At the same time, I ordered a larger set of 30T sprockets (C7000) from the shop I linked to. By changing to that, you can lighten the 5th gear to feel about the same as the current 4th gear. On the other hand, the 1st gear is also lightened, which reduces the strain from the torque, especially on uphills. I also ordered a couple of chains for the holly at the same time, changing the sprocket to a larger one requires a longer chain (about a 110-link chain according to ChatGPT).
If anyone is interested in upgrading the rear sprocket in the PK area to the larger one, there are a few extra ones in Herttoniemi for even 9e, as long as the package arrives on Friday. At the same time, you can upgrade the firmware on my EN600 for free, if you don't want to order your own.