When I played Final Fantasy VII as a child and teenager, I gave zero thought at all to strategic character building and found the late game really unreasonably hard. Basically, I would equip everyone with the weapons and armor with the biggest numbers so long as they weren't the ones with minimal or no materia slots and then I would distribute materia based purely on vibes. Cloud has spiky yellow hair so he gets Lightning and Ramuh, and his sword is big so he gets Deathblow. Barret is a big muscly rage man so he gets earth/fire magic/summons. Yuffie's portrait reminds me of Lara Croft so she gets the sunglasses in her accessory slot. Why would I bother wasting anybody's materia slot on something like Barrier when I could instead use it for something cool like exploding people? That kinda thing.

I spent my life trying the game again every year or two, starting from the beginning again and playing like an idiot and never being able to beat it and giving up. Thinking it was really cool and wanting to come back to it largely because I liked the aesthetics. And I kept on ignoring all the things I had previously ignored before because "I've played this game before, I know how it works." I made little steps forward throughout those years as I became more familiar with the genre from other games, like reading the descriptions on accessories and keeping a rotating party of my lowest-level characters but it wasn't until depressingly far into my twenties that I internalized the fact that assigning materia affects your character stats and that's when all the systems fell fully into place: you're supposed to use materia and equipment to form your party into a balanced trio of RPG character classes.

Some combinations will form a wizard, some will form a fighter, some will form a cleric. Any combat function you can think of, even a much more specific one than the cliches I listed, there's a combination of equipment and materia that will make a character into that. A balanced trio of specialists will get you much better results than three idiots who suck at everything.