If you need to stay on Xcode 11.4, try this:
xcodes
for example);/Applications/Xcode-11.5.0.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport/13.5
to /Applications/Xcode-11.4.1.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport/13.5
;You should now be able to run your app on iOS 13.5 with Xcode 11.4.