The code base for all three platforms officially supported (Linux, Windows, macOS) is the same. There is no difference in functionality available, layout, UI, etc.
This said, Kdenlive is depending on a few things outside of the dev team’s control, so overall performance and stability may be different across the OS simply because of the different architectures and what other (system) software is installed. And there are instances where something works in Linux and Windows but not in macOS, or in any other combination.
I would base my choice of OS not on just functionality or performance of a single application. There are other things to consider as well. Just my 2c.
Hope it helps with your decision-making …