The complete and utter devastation that accompanied the end of the war broke any desire on the part of most of the population to carry on the fighting. In the last few months the German military was suffering 300,000-400,000 KIA per month, almost all German cities and most medium to even some small villages had been severely damaged by bombing. Hunger and privation were widespread. In the East it was almost apocalyptic. Hundreds of thousands of civilians died as desperate people made mass treks in the biting winter with little more than what they could carry trying to escape the approaching Soviet behemoth.

Many of those that were unfortunate enough to remain were abused terribly by the Russians and these reports (horrific enough in reality while also amplified by German propaganda) brought an almost existential dread.

Towards the very end, especially on the Western front, German civilians in towns where the allies approached actually booed, hissed, and harassed German troops passing through on the way to the front, demanding they surrender rather than subject their homes to further risk and violence in a hopeless cause. They were caught between Nazi functionaries (with nothing to lose since they knew their fate was sealed in many cases) insisting on zero capitulation (violently at times) and approaching allies that would bombard towns that continued to resist rather than surrender when approached.

There was a movement among the Nazis to create the "Werwolf" resistance to carry out partisan warfare but it fizzled out with the absolute exhaustion that fell upon the German people after the war ended.

There were of course a few fanatics and there were acts of violence after the war ended but for the vast majority of Germans the last few months of the war especially had been so awful that they would do or accept almost anything as long as the carnage would simply stop. That's not an environment in which a successful guerilla campaign can flourish.

The Germans were too busy focusing on acquiring the basic needs for human survival to care about let alone continue fighting for a now non existent Nazi party that most people had come to despise (not for the ideological/historical reasons we do, they mostly blamed them for the misery that the war had brought to Germany, prominent party officials and gauleiters insisting on no surrender before fleeing with their small entourages as the enemy approached etc).