Yes, configuring icon size has become necessary after some manurefacturers started making monitors with ridiculously small pixels. You can find it in … / Preferences / Preferences / Common / User Interface / Toolbar icon size
i suspect, but i’m not sure, that this has nothing to do with KiCad but depends on the OS (at least on Linux). Some colleagues of mine miss completely the icons in the menus and i never understood why.
You can also uncheck the “Show icons in menu’s”. I normally don’t bother with icons in menu’s. I only leave them on for KiCad because I post so many screenshots on this forum.
I’m also still on KiCad V8 myself, so I suggest you search though the menu to see whether you can find something fitting. Maybe it’s a per program setting?