There was the same problem, but this SO-answer from Saranjith user solved it, while there were no other solutions in this thread: Custom Xcode 8 font does not appear in the interface designer
Basically in the Font Book, select โComputer Fonts,โ then click the โ+โ button and add the fonts again.
This happened to me after switching to Xcode 11 in Catalina from Xcode 10 in Mojave.
Sean dev
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