I've had a bunch of Pi Zero W cameras in 24x7 use for years in a very harsh desert environment where ambient air temps regularly exceed 120F, and have never had a single crash of any of them, not even a failed SD card despite being written to daily for storing motion-activated images (the sunrise/sunset is always captured). I don't even have fans on these, and they're in the compact pi foundation red and white case for camera use. It's really been quite impressive.

What I've heard is a crashing Pi is usually due to sagging voltage on an inadequate power supply, and that's probably even more an issue on the more demanding/powerful Pi4. On my cameras I just use the wall warts adafruit sells for the Pi, and haven't had any power problems.