I seem to recall the fascists losing in Germany.

This sort of sabotage is for resisting a tyrannical government where resisting more openly means death. Its goal is to hasten a tyranny’s collapse, not prevent its formation.

If you want to prevent a tyranny from consolidating its power, what you’re looking for is revolution. Use your freedom of movement to organize into local militias/guerillas and make plans to take or destroy nearby key infrastructure. Optionally make contact with other cells to track their progress and coordinate. Then at either some broadly communicated time or at a watershed moment, execute your plans. If you succeed at your objectives, help ones that failed.