A VM escape is always possible, there's nothing forbidding that to happen. But it's not probable. A VM escape exploit is very valuable, and would not be used against a low value target (or a random guy). And as soon as a VM escape exploit is found, the developers work to plug the hole.
As long as you keep both the host and the VMs updated, the probability is close to zero. If all you do is to watch videos and read documents, you could use your Whonix to download the files, copy them to a USB drive, and read the files on another offline computer.
And operation security blunders explains almost every case of users unmasked while using a VM, not VM escapes.