My wife made me watch the John Wick series when #3 came out... and I started with #3. She was pretty sure that I needed to watch the first two to understand what it was about... I was pretty sure that I didn't.
Turns out I was right. You don't need to watch 1 and 2 to understand everything that is going on in 3. You don't have to watch 1 to understand 2.
You can really jump in anywhere you want, and be up to speed withing a few seconds. The plot is really that paper thin.
You've seen movies with plots like this before. The tough guy that is the best at what he does goes out for revenge. It could be the plot from Taken... from any movie really.
The plot doesn't matter.
What matters is stylized nonstop action. The action is hard, fast, and it looks really, REALLY cool.
The story is absolutely nothing to write home about, but it's not important to the movie anyway. That's not where the fun is. Everything is paper thin, everyone knows it is paper thin....
... because we all realize that this is a start-to-finish action extravaganza and things like plots and stories in movies like this only really get in the way. Too deep and the movie starts to stink.
So, what you have is really fun, really exciting, really cool looking action... and it's entertaining. It's OK to admit that it's low on plot, because.... it is what it is, and what it is is super fun and super entertaining.