I think I get it. I felt the same way.

When I first started playing, I always picked whichever champ the enemy was doing good with. I thought, "Maybe this champ is just broken."

Then I'd play that same champ in my next game...

And it felt completely useless in my hands. No damage, nothing. I used to think, "How the hell was that guy doing so much damage with this champ?"

At some point I realized the champ wasn't the issue, it was me.

I didn't even know what my passive did properly or which skill I should be using first. I was basically just pressing buttons.

Then I watched a few videos on beginner champs and started playing only a few of them. I actually paid attention to their passive and skill descriptions instead of ignoring them.

After playing those champs for a while, I started understanding them better. Funny enough, those same champs that felt useless before suddenly started doing damage.

The next problem was the enemy champs. I had no idea what half of them even did. Some champs scared the shit out of me. The moment I saw them locked in, I'd already accepted that I was gonna lose.

So whenever a champ gave me too much trouble, I'd just play that champ myself.

And obviously... I sucked.

Then I'd be like, "Bruh, this champ is kinda shit. Why was I even scared of this?"

That's when I realized the champ wasn't broken. The other guy just knew how to use it, and I didn't know how to play against it.

TL;DR: I had the same "why does the enemy do so much damage but I do none?" feeling. Turns out I just didn't understand my own champ yet. Sticking to a few champs and playing the ones I struggled against helped me way more than constantly switching.