I had a similar experience, I took stats without calculus just because that was what was available/feasible in college, and eventually I took a more rigorous calculus based probability and stats course in my early 30s. Despite having to relearn my calculus, the difference in conceptual clarity was obvious from even the first lecture because the answer to “why does this work?” has a direct interpretation through calculus that you usually can’t get without calculus.

Feels a lot like hiking: as you get more fit you also get access to more fun.