If your Wearable app is crashing every time you attempt to update your watch--check if you have an emoji app installed and either try uninstalling it or update the app. After several hours of googling and several retries/crashes, I went ahead and pulled logs using ADB and found the Galaxy Watch 4 installer was crashing because it could not properly register a Watch Face content provider, in my case Bitmoji. It is a silly bug that Samsung can and should quickly fix, but uninstalling Bitmoji fixed the problem. I hope this help keep some of the people I see posting complaints about the Wearable installer over the past couple of months.