Highly recommend anyone see if their favorite editor can do sessions.
It's relatively resource efficient and fast, very full-featured, open source, and I can use it on different OSes and it's pretty much the same everywhere. Also it's GUI, and has a standard GUI UX.
I've never really had any problems with it at all until I started using it on ARM MacOS, where there were some weird bugs with filenames during saves (no corruption or anything, but would default to weird things and occasionally crash if the "wrong" filenames were used); but then the most recent major version seemed to fix all the problems.
VSCode is a full-fledged IDE; Kate is much simpler. Think of it as comparable to TextEdit or notepad.exe, but with more features.
It's definitely trending in the VSCode direction, but VSCode is full of surveillance and corporate API clients, and Kate is not.
It supports all your fonts, font ligatures, varying font sizes inside the same buffer, renders images inside your buffers, all without relying on a terminal emulator or Sixel support. Sounds fundamentally not TUI to me.