Unix like systems with X11 or Wayland All Unix like systems with either X11 or Wayland are well supported since ever.
Linux with X11 and now Wayland is for a long time the primary system on that Kate work happens.
Over the years it was, like most of the KDE applications, ported to various BSD variants.
Be it some mainstream Linux distribution like Fedora or a niche one like NixOS, Kate is available as binary package.
@daniel @cullmann If you cannot create yourself a bug report, could you please share some Infos here?
Which windows do you have? Can you see if Kate’s RAM use increases over time? Does it depend on interacting with Kate or also happens when the app is open in the background only?