We blocked the annoying snapd autoupdate behavior by setting a http proxy to a nonexistent server. Whenever we had a maintenance window we would unset the proxy, allow the update, then set the set the nonexistent proxy server again.
From being a production engineer for many years I can only agree: some of the brightest people of our generation spend most of their time compensating for the poor design choices of others. Not sure if this is better or worse than advertising.
Very annoying.