Curious - what is it about the P365 you like better than the 239?
The 239 is old school with the DA/SA version being the same as the P229 I carried for some years. I never used the Kellerman trigger but, from what I heard, I would not like it.
The Sig P365 is completely different. Unlike the P239, it is striker fired which gives you a different trigger feel, almost like a double action rifle trigger. Where as the P239 DA is a long heavy pull, the P365 initial pull is light and then there is a crisp let off. The reset is also shorter and, with a flat trigger, the release/reset is almost in the same spot.
Additionally, the footprint on the P365 is probably 33% less than the P239. Here is a good illustration of both.
https://www.handgunhero.com/compare/sig-sauer-p365-vs-sig-sauer-p239
I really only owned a P239 to carry with summer dress. It also was a handful in .40 S&W to say the least.