Theme/style/colours? SolusDark is very good - I have always considered Breeze to be disappointing and a weakness of KDE (the light theme is not particularly light, and the dark theme is not particularly dark).
Cursors? Breeze Dark (actually white) should be installed by default to complement Solus Dark and make the pointer stand out.
Icons? Not particularly fussy. There is a "SolusSC" theme installed which doesn't seem to do much. I am not a fan of icon themes which try to give all icons the same design language (the point of icons is to be distinctive and, theoretically, software authors could object to their brand being interfered with).
Fonts? I have switched to Clear from Noto, and consider it is easier to read (an entirely subjective opinion).
Application selection? No issues here - there are only about six applications other than basic KDE and that is fine because Web, mail, office, play music and play video is enough to start with.
The only possible change I would even consider is to hide LibreOffice Draw and replace it with Kolorpaint, which is simple-minded enough for my crude attempts at graphics 🙂