Yes, its an excellent deal, the official R&M price is now 2849€ and its without rear rack.

Indeed, Shimano has also a new freewheel body that accepts 10t smallest cog, the microspline. But its only used for the 12s MTB, not for road and there are only big MTB cassettes, the smallest is 10-45, most are 10-50 or above 50.

And during the first years, Shimano made it very difficult for third parties to obtain a license to use microspline to make hubs or cassettes.

If you decide to go for the 9-32t 11s solution with Shimano derailleur (BTW, you can also use a Shimano 105 RD-5800 derailleur which is cheaper than the Ultegra and very similar only slightly heavier) this shop has a very good price for the 3T/Ethirteen 9-32 cassette.