Electronic windows were an improvement over hand cranked, but the doors could still be opened. Though I do wonder if they have ever been the cause of a loss of life.
Absolutely, I think there were more than a few cars that ended up in the water where the occupant couldn't roll down the window and the water pressure kept the door closed. That's why in the 90s there was a huge market for window hammers and they had regular "how to get out of your car" PSAs. I think it was absolutely over blown and maybe only a few cases where someone died, but it was real.
I've used Linux for 15+ years.
Install from the repositories, if it isn't in your "app store" or installed using apt or yum or whatever your distro package manager is, don't bother with it until you're more familiar with Linux.
Your system is 99%+ of the time going to be secure as long as you don't install something sketch. You need to install it, it won't just happen on it's own, things can be hidden behind copy paste instructions so be sure you have a good idea of what each step does if you're doing that (I've never come across this in the wild, FYI). The other small percentage is a bug or something in packages (see the xz debacle) which you have little control over. The best thing you can do is just keep packages up to date.