Does the government arming the population and giving them a few weeks training really help in an invasion

This gets to the heart of successful partisan activities. Partisans primary contribution to a conflict is compelling an enemy to devote soldiers and resources to security in rear areas that could otherwise be sent to the front lines. Partisans can also provide accurate and timely intelligence that might otherwise not be available. Another function is to perform acts of sabotage disrupting enemy supply and communication.

They didn’t libebrate territory, but they certainly frustrated German efforts to exploit the resources of captured lands and forced diversion of troops that could have been used elsewhere…

It’s definitely creating a hostile working environment for the occupying forces.

Hell, the OSS had a whole guide for how to disrupt the enemy’s production, that was essentially “Create a hostile working environment”.

Isn’t the Balkans an example of effective partisan activity in WWII? As I understand it, the resistance movements controlled large areas.

Soviet partisans did real damage to the railway infrastructure which hindered the German war efforts.

Not an option: Their own comms hardware doesn’t work, so they’re relying on cell phones for their own communications.

(and I find the guy tracking troop movements through his stolen AirPods hilarious)