Your post is wise (or at least, it resonates to my best thinking on it which boils down to the serenity prayer as well.)

But I disagree that the two things in your first paragraph are equally bad.

If you think nothing is in your control and just blame others all the time - then you pass up every opportunity to make your life better, and I agree this is extremely common.

If you are on the other extreme and think you can control everything - you do end up tilting at windmills and wasting a lot of time and energy, but you also end up doing things that make a real difference in your life. It's a strategy strictly dominant to passivity.

Thus blaming others is always worse and I agree with your paragraph #2 and #3.