Alright, so I replaced the entire ignition system, and there you go, she runs again.
I want to thank everyone for the help and support!
I will replace the heat riser spring as soon as I can source one here in Germany, but it was not the issue and is stuck in the closed position because of the counterweight.
I did not have the patience to check the components individually, but I suspect the ignition coil failed (weakened) due to not having a ballast resistor (now has one) wich made it impossible for the electricity to run trough the corroded plug wires.
I hope this can help future bolters somehow.
Frohe Weihnachten und guten Rutsch
Max