Espanso is a cross-platform text expander that I would migrate my own shortcuts with a little effort. Hence, I used KM for automation workflow and Espanso for text expansion. Unfortunately, Espanso can only fulfill your requirements (1), (3), and (4) at this moment. Only KM can meet ALL of your requirements.
You might also look at TextExpander, TypeIt4Me, and Typinator, three of the most-established macOS text expansion utilities. I'm pretty sure that they can handle most, if not all, of your requirements.
Id recommend Typinator, as it is a great text-expansion app that I have used for years. I have around 24,000 expansions; a lot are spelling corrections, but many hundreds if not thousands are expansions that do a variety of things.
Yes, Typinator supports different “folders”, called “Sets” allowing you to specify which expansions, snippets, or abbreviations (called “rules” by Typinator) work in which apps. You can even expand a specific rule from another rule by using AppleScript.
Yes, you can specify where the cursor ends up after rule expansion.
Yes, Typinator supports variables, and stores there values between expansions, so the next time you use a rule that has that same variable, the value is pre-defined according to it’s value the last time you used it.
This part I am unsure of, as I’m not certain I understand your question. But you can check out their overview page, features page or learning center page where there is a wealth of information that should give you an idea of whether or not Typinator is for you.
Thanks so much. My Mac will be here on Friday - I haven't had an Apple PC since 1980, so I will probably hit a few bumps learning MacOS, but will start with Typinator, since it appears similar to FastKeys.
If I could offer one last bit of advice as somebody who also migrated from Windows to Mac: don’t try to make your Mac behave like Windows. Take the time to learn the Mac way of doing things, as it will ultimately lead to less frustration.