how to edit multiple layers at once=?

If you had told me it was about animating and not about drawing, then I would have given you a different answer. Besides, you aren't talking about layers, you're talking about frames. Of course animating software allows you to change a character, so it looks different throughout the whole movie, at least if you are creating a rig. What you are looking for is adobe animate. You only really use Photoshop for frame by frame animation. And I'm sorry, but if you think that that an animation that is reliant on drawing each frame separately can be altered so easily, you are misled. If I take a frame and change the hair color from red to brown, it wont automatically sync to every other frame, unless that character is a used in very other frame which it isn't.

Now as to how it works in adobe animate as that is obviously the program you are looking for. Simply, draw your character and turn it into a motion clip. Add the bone structure to your character, animate it however you want and if you want to change something about your character so he/she looks different during the entire animation then simply change it in the motion clip.

You can also create an adobe character animator rig and animate it using character animator, a part of after effects. Just look into the details of how that works by opening the tutorial.

I'm sorry, but if you really want to animate with Photoshop, you will be stuck with primitive frame by frame animation. Which is already a good feature considering the program is meant to edit photos, it even says it in the title

Adobe has been making professional creative products for the last 20 years and hasn't gone out of business yet, many people use there products, so they must be doing something right. Their team is more than capable.