Cats do kill an insane number of birds. We've found that attaching a large, colourful collar with reflective bits helps immensely on our cat. Birds are highly sensitive to colours, and our observation is that the cat simply isn't able to catch any birds anymore. They see him coming far too early.
As for the other points, I suspect you're overestimating the dangers, but that's not my call. I personally think no animal should be kept imprisoned in a home, though; I don't want to give any animal less freedom of movement than I have. Imprisoned pets even more depressing to me than zoos.
I've tried multiple collars. The magnetic ones always go missing, and the ones with a buckle have resulted in it being stuck in a hedge...
Our cat catches birds and rodents about equally judging on what he leaves at the door. I really appreciate that it catches mice and rats. It's unfortunate with the birds, I try to make up for it with a garden where they have ample opportunity to nest and find food.
I recommend sewing your own, or having someone (on Etsy, for example) custom-make it for you. We didn't find any off-the-shelf ones that were good enough.
Here [1] is what our "clown collar" looks like. It's just a loop. There's a hook that keeps it closed, but it's almost impossible to open it while it's on the cat. It sits so snug around the cat's neck that it never gets tangled in anything, and can't fall off, and we take the collar on and off just by pulling the whole thing over the cat's head.
My partner made this by sewing together some brightly coloured fabric with some shiny, reflective stuff.
As for the other points, I suspect you're overestimating the dangers, but that's not my call. I personally think no animal should be kept imprisoned in a home, though; I don't want to give any animal less freedom of movement than I have. Imprisoned pets even more depressing to me than zoos.