Idk about the extruder, but maybe you should compile marlin from scratch. The display issue seems to indicate that marlin has basically no idea what to do with it. Silent motherboard might not be working, because the hybrid threshold is set too low (e.g. switches from stealthchop to spreadcycle too early) or it just operates in spreadcycle. The probe can also be attributed to bad firmware. If you want to dive deeper or need help, hit me up, we'll figure it out.
Also PID tune your hotend with this command: M303 E0 C5 S210 U