Had a problem of icons always displaying properly in preview but only showing up as boxes in the IOS emulators. Went through all the usual manuals but the following 2 things were not often mentioned.
- Make sure to include “Fonts provided by application” key in Info.plist with the array of full font FILE NAMES included in the resource folder, e.g. “FontAwesome5Solid.otf
- Set the build action of the .otf files to Content and “Always copy”