The way that you're setting Desktop code font and Desktop text font looks right, but you don't see any effect because tools are set to use Custom fonts. To change this, you can go to the preferences panel MATLAB > Fonts > Custom, then either (1) set Editor, Command Window, Command History to each be one of Desktop code or Desktop text, or (2) change the font associated with Custom.
![Preferences panel for setting fonts in MATLAB online](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1569392/Preferences%20panel%20for%20setting%20fonts%20in%20MATLAB%20online.png)