I just wrote that he was not a well equiped sniper.
He did good planning as you wrote though, but the execution was poor. We don't know which of his shots injured Trump but if it was the first, he probably saw his miss and used the spray and pray tactic after. He sure was nervous also and that didn't help.
Very sadly, one man was killed and others wounded.
For me, all this story is not clear and killing the guy was a good way to never have to deal with the real story...
Even if the possibility of a total frame-up by Trump himself is very low, I can't exclude it totally. All we know is Trump was almost not touched, very small quantity of blood (even if he changed the story claiming being full of blood), a very small bandage, an innocent was killed in the attendance. Trump's fanatics and Trump himself said God intervened... A typical American story...
Maybe we will know one day what really happened. But maybe not. It's difficult to find the whole truth when the main suspect is killed by law enforcement.
We only have to think of the whole saga surrounding the assassination of JFK by Oswald and then the assassination of Oswald by Jack Ruby. Is this whole story reduced to these 3 peoples? It seems impossible to me. But that said, sometimes the most improbable things happen like the election of the clown in 2016.
When a clown enters the palace, he does not become a king, but the palace becomes a circus. The years 2017 to the end of 2020 have demonstrated this.