It isn't complicated, nor should it be complicated.
For the "average" person, this mythical unicorn of a person, all they need to do is general exercise.
Get stronger in the main movements, you know, the big compound lifts:
Upper Body Push Upper Body Pull Hip Hinge Knee Bend
Do some heavy, with low reps. Do some lighter with higher reps. Do the "other stuff" that takes you outside of the saggital (front to back) plane, stuff like Turkish Get Ups, Windmills, walking, running etc. Do some mobility that moves you through less common movements
And you're golden.
Yes, an athlete training for a big event in a specific sport, that's a little more nuanced. As is recovering from / managing injury.
But for most people, most of the time, it's simple (if not easy)
Now, get to it!