Man we’re the same person lol I too use geany for basically everything and tried out Kate because it felt more feature complete but it just isn’t. There is nothing I can do on Kate that I can’t do in Geany that is relevant to me. Mostly Lua programming and markdown editing. I’d say just make a theme that fits the KDE style and use some breeze icons in the editor to make it feel more like it belongs and use what works and is comfortable. I still use gnome and so I made a gnome builder editor theme and made the whole editor look like gnome builder and it works wonderfully. I bet the same is possible for kde.