In theory Dmowski as a right-wing figure should get you there but I do not believe that some pseudo-fascist Poland would be his creation, instead I focus upon Piłsudski. To be fair I am working on an "independent" Poland under a CP "victory" scenario, likely tugged between Imperial Germany and surviving A-H. Piłsudski harbors more animosity toward Russia and I think Russian revanchism, especially under a still communist Russia, could push more authoritarianism from him, not a genuine nationalist surge but very much patriotic, anti-communist and socialist underpinnings. With a foreign King, he might have more opposition and be more top-down looking at ruling Poland as a pro-Austrian figure assuming he has a role. While I do not believe he is a fascist Piłsudski showed his strong hand after the 1926 coup, a state of affairs very different from how I envision Poland evolving, but I think illuminating. He might be accused of being an Austrian toad, trapped between the ailing A-H, wary Germany and revanche/revolutionary Russia, still hoping to expand Poland with Lithuania who is likely fully carved away to be a German satellite.
My deeper concerns are how anti-Semitism bleeds into Polish nationalism and what struggles occur to get true independence. And even a smaller Poland has more ethnicities than just Poles. As it was OTL Poland had some dark undercurrents that could rear up, especially if A-H does begin to break upon its own fracture lines exposed by war, revolutionary and independence minded folks are still crammed in and Poland as an A-H satellite might be swept into a different struggle. I am loathe to recast such a historical figure as Piłsudski against this or argue he will be the villain. But that is what these exercises can be about.