I couldn’t find exactly where I said keep it around 4200hz.
This post: https://toidsdiyaudio.com/forums/discussion/first-crossover-design-any-feedback-appreciated/#post-26508
2 x’s FS is norm, but you could try a few hundred Hz lower, say, 3600 – 3800 Hz. that’s in the 75% range of the 2x’s standard. Might smooth things a tad more with that peak around 1800-1900 Hz and the dip around 2400Hz. Or not. That’s the great thing about using the software to design – easy to test “what if’s”.