Upgrade to 5.5 Freezing at 73% Compiling Blueprints - No Errors in Log

Did you try adding build order settings to your target files?

inside of

public MyGameNameTarget( TargetInfo Target) : base(Target)
{
IncludeOrderVersion = EngineIncludeOrderVersion.Unreal5_5;
 DefaultBuildSettings = BuildSettingsVersion.V5;
}

when upgrading a c++ project the engine can mess up the build order due to changes in the engine.
You have to then tell the engine to build in the specific order.