Q.Shot leaf and canker in cherry tree
I moved into my property a year ago. There was a large cherry tree, about 25 foot tall and a spread of about 20 foot. It has severe leaf shot and also bacterial canker. Is it worth treating or would it be better to cut it down? I cannot reach all of the affected parts to treat.

That's such a tough call.
I love to give my trees and plants every chance to live, but serious tree issues that could spread to other trees is concerning.
Here are links to the treatment course for the above mentioned issues just incase you would like to continue treatment.
I wish you luck.
https://www.gardeningknowhow.com/plant-problems/disease/shot-hole-disease-fungus.htm
https://www.gardeningknowhow.com/plant-problems/disease/weeping-amber-in-trees.htm