They’re wild animals. You pretty much got two choices if you live in an area that has big cats:
make your fencing full prison fencing
make sure you’re not leaving stuff they will consider food (your pets, maybe your kids) out there
That’s really all you’ve got. I’ve seen a bobcat (which really aren’t that big, two to three times the size of a house cat) hop to the top of a 10 foot wall and go down other side, probably looking for breakfast.
A mountain lion can jump 30 feet and easily clear a 10ft fence.
I've had a lion sneak behind me while I was bent over running a big chainsaw in broad daylight.
There is no such thing as protection from big cats without hunting them to the point that they are afraid of the smell of people. It helps to have a defensive dog present to warn of an approach. If nothing else, it gives me time to unholster my gun.