You've Been Playing Cloud All Wrong In Final Fantasy 7 Remake
Cloud stylizes himself as an elite soldier turned mercenary, able to take down any enemy thanks to the power of his Buster Sword. That might be what he boasts, but Cloud can run into trouble if he doesn't utilize his powers properly. Final Fantasy 7 Remake isn't a game that can be won by button mashing. If you've been relying on the Buster Sword and nothing but the Buster Sword, you've been playing Remake all wrong.
Cloud is a melee-oriented character, who should only use Materia when the occasion calls for it. Deadly Dodge Materia can come in handy, but you'll want to save most of the magic for mages like Aerith to handle. Cloud should be focused on dealing damage, which can be enhanced with Elemental Materia, depending on the foe that you're facing. If you pay attention to Elemental weaknesses, you might be able to get in some critical hits.
The Buster Sword is handy, and you should return to it even after receiving the new Iron Blade in Chapter 3. Learn the "Triple Slash" special ability from the Iron Blade and then go back to the good old Buster Sword. Even though Cloud might not strike you as a literary scholar, you'd do well to purchase him some reading material from the Moogle Emporium. Check out The Art of Swordplay Vol. 1, which will give him some much needed skill points for that iconic blade.
The Buster Sword is key to being a well-rounded Cloud with the flexibility to adapt to just about any battle. If you'd rather just try to deal as much damage as possible and go the button mashing route, you're better off with an offensive weapon like the Nail Bat, which has an severely increased chance of landing critical hits. That said, if you value damage over all else, then you can boost the Buster Sword's damage with Lightning Materia. It looks really cool, too.
To break it down: use the Buster Sword with the Materia that best suits the battle. Lightning will cover up weaknesses, Elemental can boost attacks, and Deadly Dodge will keep Cloud on his toes. Although Cloud isn't exactly the elite soldier he says he is, he can fight like one with the right build.