This is pretty much the exact same way I use Sublime (except the git diff stuff is done in Sublime Merge, which is a separate application)
I've tried switching to Kate a few times since I prefer open source tools, but it feels like a major step down UX-wise. My primary workstations have been Linux with KDE Plasma for many years, but I am not a huge fan of the KDE aesthetics (which seems to aim for maximizing clutter).
I'm generally not a picky person, but my text editor is by far my most-used tool, so it's an exception.