Others may know better than me; but my recollection of what I've read over the years is that the line of the KPD was unswervingly pro-Soviet. But they did try to focus on the threat of the Americans (they sought to make America be seen as the main threat to Germany and to Europe), on economic issues and union struggles, and against Adenauer and especially re-armament. But, yes, they had a difficult path, Certainly much more than in France, or Italy, or even in the UK.