G2S dual extruder firmware issues

[g3x123]

Hi everyone!
I recently bought a Geeetech Delta Rostock G2S, after fixing dead on arival parts I got to the calibrating and finaly printing part which lead to another series of issues.
Problem 1: Printing doesnt print anything! Manual extrusion works fine, forward & reverse, both extruders. When printing the printer is moving and 'printing' but no filament is feeding, so nothing is actually printing.
https://www.youtube.com/watch?v=hDqWUH5Aac4&t=28s

Problem 2: After finding dozens of firmwares, only ONE would let me print something, single extruder.
-> manual extrusion: works on both extruders, after homing and then switch to the other extruder. If not homed, all axis move up and crash.
https://youtu.be/rskrL92WaQs
-> printing: same happens, on extruder switch all axis just move up and printer starts printing in mid air.
https://youtu.be/gHTwbG0JgWo

Can someone PLEASE HELP ME? I have been searching for weeks on this!