Blender by far is the most annoying and most inconvenient program I ever used. How the heck is it that I MANUALLY HAVE TO GO TO EVERY ARMATURE AND EVERY MODEL AND CLICK ON ITS SHADER TO SELECT EVERYTHING? IM TRYING TO ANIMATE AND MOVE THE KEYFRAMES IN MY TIMELINE AND I SIMPLY JUST WANT TO SELECT EVERYTHING IN ONE CLICK INSTEAD OF MANUALLY GOING TO EVERY SINGLE THING. BLENDER IS ABSURD.
The Timeline might not be the best place for this, but in the Dopesheet, you can disable the “Only Show Selected” button and then A will Select Everything:
But maybe I misunderstood what you were trying to ask.