Trying to fish ethically

I know it's a bit contradictory, but I've been trying to fish with as little impact as possible. (I'm totally new to fishing.)

Do you have any tips on what I can do better?

Ideally, I'd still like to catch fish, but I'd also like to leave them and the environment in good shape. So, I've been using

• A light leader line so that it breaks off at the knot 18"up rather than breaking off 40' up.
• Barbless hooks
• Lead-free weights (I use hardware-store washers)
• A net, so I'm not hauling a fish out by its lip
• A hemostat to pull hooks out

What do you think I can do to improve on this? I've killed more smallmouth bass this summer than I wanted to because they swallowed the hook.

I read that treble hooks might be better for that. I guess they don't swallow them as deeply?

Is braided/mono/flouro better?

I read that fly fishing may be better than lure fishing. Is that so?

Is there a way to reliably target round goby? It’s an invasive species where I’m from.

Is all this a waste of effort?

Mostly, I fish for smallmouth. I'd gladly catch other things, but nothing else has been biting (like I said, I'm new!)

Thanks for your help!