I have updated Xcode 12.1 and it contains iOS 14.1 simulators. My widgets worked well with the previous Xcode and simulators(iOS 14.0), but since they were updated, empty widgets appear on iOS 14.1 simulators.
The workaround would be to use a real device instead of simulators, but it is quite annoying and it can be a trouble because I don't have all screen/widget sizes of the devices.
Small and medium size widgets are quite slower than before but they showed the contents which are not refreshed well.
Large size widgets display no contents and it shows only white empty backgrounds without any contents on them.
The workaround would be to use a real device instead of simulators, but it is quite annoying and it can be a trouble because I don't have all screen/widget sizes of the devices.