I view the first in a vacuum because the others actually harm it

Lol I do the same thing! If I watch any of the sequels I view them essentially as fanfic. Your point about emotional payoff in the first is really good too. It’s easy to forget watching the sequels that the dramatic core of the first movie was John’s grief for his wife. The dramatic core of the sequels is little more, as I remember, than the convoluted bureaucracy and politics of John trying and failing to be left alone.