do you just have the R785 as shifters? They will still work with R8070 brakes and everything else (FD, RD etc.)
I started collecting bits for R8070 groupset for the canyon so far have only got junction boxes and the battery, if I decide to get a whole groupset I can sell you those bits cheap.
That's not bad, but would need to shift the R785s, need to rethink this...