Small update. Installed some components:
- Neco bottom bracket
- 105 r7000 Shifters, FD and RD
- Shimano XT FC-M730 crankset with 48/28 TA chainrings on the inner and middle position
- Fabric Scoop saddle
- ZIPP Service Course 70 XPLR handlebar
- Ultegra SPD pedals
- Blackburn bottle cages
- Mavic Aksium wheelset (squeezed frame from 135 to 130mm)
- Panaracer Gravelking SK 35mm tires
Not sure about the STX Canti brakes. I ordered some really cheap XLC Mini V-Brakes (25 EUR for both incl. brake pads) which should work great with the 105 road shifter...maybe wait for those to arrive and install them first. Then testing and handlebar tape to finalize the build.
Maybe, I also try to find a 0 offset seatpost 26.6/26.8mm - but not easy to find. I'm pretty much as forward as I can be now...