Cabbage is right the accuracy of any analysis here will be a good guess at best...In watching the second video several times and trying to pause it at various points in the swing you may want to consider how early in your swing you lose connection between your hands and your shoulder. This is only an impression... and if you work with someone in person the impression may be incorrect with more data points but it would appear that you are disconnecting early in the swing. When you disconnect too early it results in early commitment to the swing. This in turn can lead to some of the symptoms and inconsistency you mention. Welcome to the site and good luck!