Question about eligibility (confusion on naturalization / military paradox)

Hello, I posted on r/AmerExit and r/poland before being directed here. Hoping to get input about eligibility for Polish citizenship by descent.

Dates are to the best of my knowledge. My great-grandfather was born in in Poland in 1905. He emigrated to the US in 1922. He was naturalized as a US citizen sometime between 1930 and 1940 (I know this via census records, but I don't know the exact year of naturalization). He was registered for the draft in the US pre-WWII but I am almost certain he did not serve in the military.

I'm somewhat confused on the military paradox, and also confused on whether US naturalization in the 1930s would have meant loss of Polish citizenship. He married an American born in the states, and all more recent ancestors were born in the US.

All input appreciated!