The Teutonic Knights were almost comically bad at what they were actually supposed to do, i.e. converting the pagan Balts to Christianity

The Prussians, Latvians and Estonians hated the Knights so much that pagan practices became a form of resistance to their rule; and the Knights themselves devoted all their resources to fighting and not so much to converting...

The problem was that the Knights were designed to attack and conquer pagan territories, but they didn't have much of a plan for how they would actually convert them

And they were victims of their own success, perpetually trying to find excuses to keep the crusade going even when it was patently obvious (after the conversion of Lithuania in 1387) that there wasn't really anyone left to crusade against...

So the Knights just became a destabilising force in the region, deliberately stirring up trouble whenever they could in order to weaken their neighbours

And there was little incentive for people to convert under the rule of a monastic state that treated converted people pretty much as badly as the unconverted ones...

So full-blown pagan sacrifice was still pretty common in Estonia at the end of the 17th century...