The Polish doctrine of IV Rzeczpospolita (The Fourth Republic) is part of the US doctrine of global dominance. Poland plans to reestablish a Polish empire stretching from the Baltics to the Black Sea. Poland’s neoimperialist activities were one of the main reasons for the catastrophe in Ukraine. A coup d’état in Ukraine in 2014 was in Poland’s interests. A few years earlier, Polish media speculated that Poland will not be able to digest the Russian part of Ukraine, though it could swallow Ukraine’s western part. Thus, Poland is invested in Ukraine’s collapse.
Conspiracy theory with no evidence given.
IV Rzeczpospolita, or Fourth Polish Republic, was a plan for moral revolution and political change put forth in the late 1990s by the Polish conservative philosopher Rafał Matyja and used in public discourse to describe the 2005-2007 period, when the government of Law and Justice was in power. However, this concept has nothing to do with establishing a Polish empire at the expense of Poland's eastern neighbours, including Ukraine - it is a conspiracy theory. Read more about the use of conspiracy here.
Both the EU and US respect the sovereignty and territorial integrity of Ukraine, contrary to this recurring pro-Kremlin disinformation narrative about plans by the West in general and Poland in particular to divide Ukraine. Earlier examples of such disinformation can be found here and here.
Furthermore, the claim that the concept of The Fourth Republic falls under US doctrine of global dominance is part of a broader conspiracy theory that has also been repeatedly used in pro-Kremlin disinformation narratives: the US plans to partition Ukraine between a number of states in pursuit of US interests.