In my Program.cs:

ScanAndMapGrpcServices(app);

static void ScanAndMapGrpcServices(WebApplication app)
{
    var currentAssembly = Assembly.GetExecutingAssembly();
    var allTypes = currentAssembly.GetTypes().Concat(
        currentAssembly
        .GetReferencedAssemblies()
        .SelectMany(assemblyName => Assembly.Load(assemblyName).GetTypes()))
        .Where(type => type.Namespace == "<my namespace>"
                       && !type.IsInterface
                       && !type.IsAbstract);

    Console.WriteLine(allTypes.Count());

    foreach (var type in allTypes)
    {
        var method = typeof(GrpcEndpointRouteBuilderExtensions).GetMethod("MapGrpcService")?.MakeGenericMethod([type]);

        object? invokedBuilder = method?.Invoke(app, [app]);

        if (invokedBuilder is GrpcServiceEndpointConventionBuilder builder)
        {
            _ = builder.RequireCors();
        }
    }
}

When running on Release mode, I got this error
throw new ArgumentException(SR.Format(SR.Argument_GenConstraintViolation, i.ToString(), type, definition, type2), e);
But in debug mode it’s totally fine.
At first glance, I thought my assemblies are trimmed but then I print Console.WriteLine(allTypes.Count());, both Debug mode and Release mode returns 22.