That sounds more like switching to macos being terrible. If I am used to kate on linux, windows,..., then I expect it to just work if someone hands me a mac with kate.
If you additionally want mac-style shortcuts as an option that is fine, but defaults should be consistent.
There's no app that uses the same shortcuts in all OSs because that's just stupid (amongst other reasons, because the shortcuts would conflict with the OS's own shortcuts, just to mention one obvious reason). You need to default to the OS's defaults, and maybe have an option to try using another OS's defaults (like other IDEs do).
If you additionally want mac-style shortcuts as an option that is fine, but defaults should be consistent.