Idk, LibreOffice UI seems pretty decent for me.
IMHO, Debian is not the best choice for KDE, especially if you are on Wayland. KDE is a bit more buggy than GNOME, but bugs are fixed constantly at a fast pace, and Wayland support gets better. With Debian, you are stuck with the old version and have to wait 2 years for bugfixes. Kubuntu would be a better pick since it has interim releases with more recent KDE and also official backports with fresher KDE version.
Better tools for graphic design. Maybe a port of the Affinity suite or a big push towards GIMP, Inkscape, and Scribus development. GIMP... I feel like people dreamed for more than a decade for essential photo editor functionalities like CMYK support and non-destructive editing. At least the first one is coming in the next version(partially).
It's not a default but I just changed it to tabbed view in the settings, picked Sifr icons in the settings, and installed adw-gtk3 theme on GNOME which makes gtk3 apps blend more with the default libadwaita GNOME theme.