At bug 426414 it has been stated, that in the settings dialog the page selecting an icon style different does not support any entry except 'system.'
STEPS TO REPRODUCE
1. download portable package of kmymoney from binary-factory.kde.org or kmymoney.org/snapshots.php and unpack
2. start kmymoney
3. enter settings dialog and select page 'symbols'
4. change the selected entry, press save and restart kmymoney
The used icon set is not changed.
On Windows that settings page should not be visible to not confuse the user
KDE Frameworks Version: 5.65
Qt Version: 5.11
The availability of different icon sets depends on the installation of corresponding icon sets, of which only breeze and breeze-dark are available for Windows, and a correct matching of the search paths between Qt5, kicontheme and the application.
Quite sure I removed the icons settings panel for Mac and Windows in master already.
Git commit 32f65ac10c9cfa098c16698fafc9d9aca283cd4d by Thomas Baumgart.
Committed on 17/04/2021 at 07:48.
Pushed by tbaumgart into branch '5.1'.
Remove icon set selection from Windows and Mac builds
M +6 -0 kmymoney/dialogs/settings/ksettingskmymoney.cpp