German-Polish relations are strained. This also has repercussions for NATO. The partner nations have noted with concern that there has been repeated discord between Warsaw and Berlin in recent years.

The two countries could not be more different in their military positions. While the Poles clearly recognize the sense and necessity of their army, the opposite is the case in Germany.
While service in the army is an honorary service in Poland, fewer and fewer volunteers enlist in the army in Germany. Mostly for economic reasons.

Poland invests strongly in Military – Germany does not

The equipment is also handled differently. In Germany, NATO’s two-percent target and the loudly announced special funding have been quietly scrapped. In Poland, it has been made clear that the defense budget will rise to 4 percent of gross national product.

https://www.dw.com/en/poland-to-ramp-up-defense-budget-to-4-of-gdp/a-64555544

While Poland is rearming, Germany is not replacing the ammunition and material it gave to Ukraine. A disparity that worries other nations.

The Finish Institute of International Affairs has published an opinion article that discusses these concerns and roles out a solution that brings Finnland into a mediating role.

Finland should play coordinating role

This document discusses the evolving role of Germany and Poland in European defense. Both countries are strengthening their armed forces, with a focus on developing strong land forces. They are responding to changing European security dynamics, including NATO’s large-scale defense plans. Germany is increasing its military presence in Lithuania and committing troops to NATO’s New Force Model, but faces recruitment and equipment challenges.

Poland is significantly boosting defense spending and acquiring various weapons systems, although concerns exist about compatibility and long-term planning. While competition for a Central European power role is possible, strained relations between Poland and Germany hinder cooperation. Coordination between these countries and NATO is essential for the alliance’s credibility, and Finland should play a coordinating role due to its strong military presence in Northern Europe.