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.

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 (partially).