It looks like things were working normally here, and it would have opened the first time if you kept waiting. The issue seems to be that your library is stored in iCloud Drive (or perhaps in Dropbox), and you had selected the optimized storage option. That means that macOS can offload the files so that they’re only stored in the cloud, and then when you open the library EagleFiler has to wait while many of the key files get downloaded.
This works the same way in the current beta, which will be shipping soon.